Spawn interval fixed per level

[Simon]

Thanks for the response. Gave me lots of opportunity for reflection. After sleeping over it, I feel I can dissect it fully. >_>;

why this couldn't simply be left to the level designer's discretion as it is today.

It is an unfitting feature that has not been pulling its weight.

To go from the game with everywhere-fixed SI to one with rarely-used variable SI, we incur these costs:

1. Allow the player to change the world in a new way, unlike anything else in the game. We may be used to it because L1 has it, but the difference of variable SI to skill assignments is glaring. If wanted, I can elaborate on the value of simplicity and conciseness in game design.

2. Make two buttons in the game UI, and display the current value. The buttons alone are highly nontrivial, taking left and right clicks. Setting a number freely in a game is UI bloat -- this is what city simulation games offer, or "Myliege, how much grain do thou wish to distribute to thy peasants?"

3. Introduce these buttons to new players. There is a ton of problems hidden here that have been bugging me for years.

• A time limit is self-explanatory, provided you notice it's there. These buttons are not.
  
• They aren't needed in 98 % of the levels, and don't scream "use me" once they are.
  
• They stop affecting the world after all lixes are out. Even when they do something, it's not obvious what they do -- people will change the SI by 1 and see no difference. They violate discoverability.
  
• As a comparison, the time limit doesn't advertize itself at level start either -- this bad visibility has been reported as a bug.
  

4. Force even experienced players to check another level environment setting -- whether or not the SI is variable -- each time they play a level.

5. Make a second setting in the editor that depends on another editor setting, and must be changed along with it. (UI improvement would be a checkmark in the editor for fixed/variable SI, fixed by default. But this doesn't leverage any other numbered reason or bullet point, and it a rather high amount of work compared to the benefits.)

What benefits do we get?

Levels don't need variable spawn interval to be solvable. Even if they were thought to need it, they don't need it, or can be adapted surprisingly easily.

An exception are levels where SI fiddling is absolutely the main idea. And here, I value game design over pulling along every bit of accumulated tradition. If only 5 levels out of 500 would have to be culled, it's already a success.

Nepster has claimed how it helps execution. Yes, if the level designer can speculate on the player using SI, the level designer is less inclined to ease execution otherwise. I would like to see levels that can't be adapted accordingly.

So, the variable SI brings way less than the time limit -- unless unfixable levels are dug up, all we lose are the very few levels designed explicitly around SI changing. Its cost is much higher, and doesn't afford this.

We handle these issues by recommending best practices for level designs.

Time limit: This isn't a method to affect the world as a player, which is the main reason I want to get rid of variable SI. As discussed, I have claimed this has more benefits in return, at lower cost. Also, I'd compare "all levels have unlimited time" closer to "all levels have SI 32" than "all levels have a fixed SI".

Builder stretching: Allowing builder stretching in the physics is simpler than disallowing it. Disallowing variable SI, or disallowing time limits, removes complexity from code, and from the player's mental model. But disallowing builder stretching would introduce code that checks for how long a walker has been walking since being a shrugger last, and then disallow builder assignments here.

Alternatively, the shrugger would have to walk to the tip of the brigde before shrugging. I've considered this before, I have shunned it due to looks and tradition.

I'll concede that even the historic evidence suggests the game designers at DMA do not value variable SI as a level solving tool, starting with the fact that they removed it as soon as they got to Lemmings 2

Hmm, L2 and L3 don't have it. They don't make up for crowd control too nicely, but that's an issue with level design and other game features.

Lemmings 3D and Lemmings Revolution weren't designed by the same team anymore.

I assert that the two teams behind L3D and LR fell into the same trap as most developers of Lemmings-like games: Copying features from L1 without reflecting on their merits.

eliminate otherwise fine levels in the original game like "Just a Minute (Part II)" and "Flow Control".

Flow control can be fixed with runners and longer walkways. :-) Just a minute 2, I'd have to take a look.

I'm not trying to cull variable SI from Lemmings 1, but from Lix, where there are better features for the desired effects.

-- Simon

PS. Conundrum can be adapted by

Spoiler

setting the SI to 4 and giving one runner. (Or two runners, as red herring.) The level is short enough that the runner can't build over the lava without stalling the crowd.

[ccexplore]

Well, it was clearly going to be an uphill battle arguing for keeping variable SI, given that it is definitely not used often throughout the history of both official games and custom levels.  I think I gave my best shot at playing devil's advocate for variable SI (and of course there's always NeoLemmix to continue doing things that are deemed too anti-lix ).  It is a good point that the desired effect for variable SI is usually to selectively compress a few rodents or to get some to come out (and therefore getting to certain places) sooner than the normal flow, but those things can often be arranged instead via skill assignments, and doing it those ways may arguably be even more interesting for the level's solution.

For those who are looking at adjusting existing levels accordingly, do keep in mind that runners can be somewhat more powerful than the effects of variable SI due to permanence of the skill, so make sure to also think about whether the changes may introduce new backroutes.

And don't forget to check your timed levels.  If the time limit expects the ability to minimize the SI towards the end, you may now need a longer time limit instead, and that may introduce backroutes as well.

[Nepster]

Nepster has claimed how it helps execution. Yes, if the level designer can speculate on the player using SI, the level designer is less inclined to ease execution otherwise. I would like to see levels that can't be adapted accordingly.

In any sufficiently complex system (such as Lix), you can remove any non-essential part and still adapt everything. E.g. you could remove all time limits or all traps or all other objects like springs, steams, ... or the ability to rotate terrain pieces or level wrapping or... Nothing essential would have to change!
The main point is not, that SI changes cannot be removed, but that they help level creators and players.

To get you some data, I manually went through (most of) the collected replays for the community level pack (version 2015-06-22, viewed with an old version of Lix) to look for replays where SI changes are an essential part of the player's solution, but were not needed in other (respectively intended) solutions. Here is the list:

Spoiler

everywhichway_Akseli
fearofheights_sekti
halfwaydownthestairs_clam
halfwaydownthestairs_geoo3
impetus_geoo2
jacobsladder_sekti
labyrinthofdespair_Akseli
labyrinthofdespair_proxima
lixcannon_sekti
lixferanda_Nepster
lowprofile_Ramon (same lowprofile_geoo)
overmyhead_mobius
slippingagain_Akseli
slippingagain_Ramon
snowjump_geoo
survivalofthefittest_geoo
thebottomless_Ramon
thehotelinhell_Akseli
thisisastickup_Ramon
trapeze_clam
waitwhyisthereatree_Ramon

And here some levels, where all solutions use different SI changes. These levels will likely make problems when adapting to fixed SI:
thatpeskygap
ticktoxic
toofartowalk

To go from the game with everywhere-fixed SI to one with rarely-used variable SI, we incur these costs: ...

If anything, points 2 and 3 are bad UI and not an intrinsic problem of SI changes. And it's not that bad in my opinion - you display ingame help texts!
Point 4 doesn't hold because players will have to look at the SI even when it is fixed.
Point 5 I don't understand: Assume no SI change is required in a level. Why is fixing the SI then better than allowing changes?

Flow control can be fixed with runners and longer walkways.

There you have the same problem as with We're in this one together: I would rather change the SI than find the correct placement for the runners. We changed the bombers to untimed ones to remove placement problems, so why reintroduce them?


One more point: If you are creating a game without level editor, then you can expect that the level creators are experts and impose such restrictions like fixed SI, ... Experts like us here will surely find a way around it.
But having a level editor, you want to give everyone enough different tools to make their desired level. And SI-changes is one tool here that simplifies the level creation process. And I prefer people creating levels with SI-changes (even when the level can be modified to remove them) over people getting frustrated that they cannot produce a level featuring their level idea. Or they would create levels needing very precise skill assignments. I must confess that two years ago, I would have kept the old version of Heed the Traffic Light even with the current mechanics and fixed SI - just try it and see what I mean .


Suggestion: Why not keeping SI-changes possible, but try to modify all current levels so that one doesn't need that feature? Then players may choose whether they prefer SI-changes or solutions via better skill usage.

[ccexplore]

I think the main tension here may be that unlike past game mechanic changes that have since been incorporated, this is the first time (at least as far as I can recall) we are proposing here a game mechanics change that isn't actively solving an existing problem provably experienced by actual players.  ("Here" because Simon certainly have had many other proposals on IRC that have yet to reach the point of a forum discussion thread. )  And the ability to vary SI can definitely be very powerful, giving you quite precise control over the flow of rodents with 0 costs and almost no side effects (neither of which would be true with skill usages).  So it makes sense that the option to vary the SI can be helpful from time to time, and can be appealing for some levels to require its use.  At the same time, it clearly is not of much help in the construction of an actual path to the exit unlike the core skills that modify terrain, so it is also no surprise that most levels don't need it.

[Simon]

Nepster, thanks for making the list to try.

I'll be meeting with Icho tomorrow, he's gonna show me a couple more examples of his own.

I've begun going through the suggested replays. Here's my results for the first 5 levels, and Pesky Gap. My interpretation: The players use the variable SI because it's available, but it doesn't make their solution easier to execute. Every time, once the solution idea is formed, were the players subjected to fixed SI, they'd have executed the idea similarly fast and precisely. Concrete reasons for this interpretation:

Spoiler

Every which way: The key is to have exactly 2 turn in the miner hole. Once you know that you want to do this, it seems to be of similar difficult with/without spawn interval. Of the 5 levels examined, this the only one where I'm unsure about variable SI; all others are clear cases how it's unneeded.

Fear of heights: Spawnint change is purely a fast-forward here -- give fewer lems, or a faster SI.

Halfway down the stairs: People use this to cluster the lems faster, which would cluster anyway. In particular, if you do nothing but wait, you can still bat about 7 lems to the top of the first step.

Impetus: No matter what you try, the crowd is safely contained. This level should have SI 4, it can't lose anything, but allows easier timing.

Jacob's Ladder: Many spawnints seem to work, and they all lead to equally beautiful solutions, with the same idea. Let's fix one of these working spawnints at random -- that cannot not kill the puzzle, because most guessed spawnints would have worked, too.

Pesky Gap: The straightforward adaption works: Give fewer lems, give runners. I mentioned this in IRC on the day I made the thread. I find the entire level a bit lush, but that opinion is off-topic.

I found this general argument of yours to pull most weight:

There you have the same problem as with We're in this one together: I would rather change the SI than find the correct placement for the runners. We changed the bombers to untimed ones to remove placement problems, so why reintroduce them?

This is an excellent point. Is it applicable to levels other than mostly-SI-centric levels, which I don't care about much?

But having a level editor, you want to give everyone enough different tools to make their desired level.

When a level requires too much precision, it sucks. People will complain to the level designer, and the level designer will improve. When several levels require finding out the correct SI first, they suck. People will complain at the level designer.

People should not accept badly-set SIs, even when they can change it during play. They should report the bad design.

If anything, points 2 and 3 are bad UI and not an intrinsic problem of SI changes. And it's not that bad in my opinion - you display ingame help texts!

No, it is worse than fixed SI. If you want variable SI, you have to implement it somehow. No matter what you do, it's more cluttered than no button at all.

Point 4: I don't mean that players need to look at the exact number. I mean that players need to look at whether or not the spawnint can be changed. If it's fixed, the exact number isn't relevant too much; you have to experiment in the level anyway.

Point 5: Fixing the spawnint makes the player concentrate on the core mechanic of the game, assigning skills to lixes. So far (5 levels of your list examined), I haven't seen a good example for how variable SI gives power or comfort over the well-designed fixed-SI version. If this holds true for the remainder of the list, then fixed spawnint is comparable to giving unlimited time, instead of an overly generous time limit: Less to worry about, without losing puzzle scope.

Suggestion:

We shouldn't give options that don't do anything useful, or are mere placebos. Again, this depends on further examination of your list; so far, I'd lump 5/5 use cases in the placebo category.

-- Simon

[Simon]

isn't actively solving an existing problem provably experienced by actual players.

NaOH and I feel awkward when relying on it during play. Unlike with the basher staircases, I've discussed my hunch a few times before being prompted by her around christmas 2015.

Other than that, you're right -- in particular, my argument wasn't built on that awkward feeling. The entire reasoning behind the proposal is different from previous mechanics discussions on the forums.

I find variable SI unnatural, but Icho, for example, believes it's a core part of the game, with low learning curve. Proxima may still post a write-up later. All proponents of the variable SI are level designers.

Clam suggests fixed SI, an interesting exception for a level designer. Mindless and ADmiral suggest fixed SI, too, having followed the discussion without being entrenched in level design themselves.

-- Simon

[ccexplore]

Variable SI is definitely not the "very core" of the game when you compare it to the terrain-altering skills, as aside from rare exceptions you almost always need the latter to build a path to the exit.  At best you can probably compare variable SI to the other skills like climbers etc. that are typically used to get selected lixes deviate from the flow of the crowd, usually to get to otherwise inaccessible places for building the path to exit for the crowd.

I can no longer remember exactly how I learned about changing the RR when I first played Lemmings 1, though I don't remember ever running into trouble due to not knowing it is possible--even though there is no explicit tutorial level for it, it works differently compared to assigned skills, and you do need to change the RR in order to solve some of the later levels in the game (almost always in conjunction with a tight time limit).  So I definitely see it as having an apparent low learning curve, and thus I don't think I will put as much weight as you do on some of the arguments you listed regarding how variable SI can be problematic.  (Granted, with the current design of the skills toolbar in lix, the buttons for changing SI are inevitably less discoverable starting from their smaller sizes.)

I think for the proponents, the main appeal is that what may appear initially to be a boring feature can actually be a quite useful and powerful level solving tool.  I think it also carries less side effects than having to add additional skills to allow the player to achieve the equivalent effects, as adding additional skills tend to risk opening up backroutes.  And it can be easier to use as Nepster points out in his comparison to changing bombers to untimed.  Even if there's just a single instance of a temporary SI-bump in the level (so presumably it isn't in the "too-SI-centric-for-Simon-to-care" category?), it will be inevitably easier to achieve the desired effect with varying the SI compare to working out by eye where a running Lix will meet with a walking Lix.  [Indeed, it seems if variable SI is to be replaced by giving additional skills, the player would probably prefer other skills instead to achieve clumping of the lixes, like maybe jumping, batting, walkers, air-bashing etc., as pretty much all other methods except for runners would allow you to achieve the desired distance between lixes ahead of time instead of having to time it (unless I'm missing something about how Simon's using runners as a substitute for variable SI in the various examples; admittedly I haven't really looked at most of those levels yet).]

It makes sense that all proponents of variable SI so far are level designers, as there seems to be no level design reason to advocate for elimination of variable SI, given that no one is forced to use variable SI today when designing levels.  Where people stand on this topic depends on the problems one perceives variable SI leads to when playing levels (or learning the game), weighed against the perceived benefits variable SI brings to level design and solution execution.  Someone who likes variable SI would naturally be less affected by the problems while more appreciative and preferential of the benefits.

Anyway, do you realistically expect that you may actually change your mind about this over an example level?  Given the relatively low number of levels where variable SI is even relevant, and the high weight you attach to the perceived benefits of fixed SI (and perceived problems of variable SI) that you've listed, I kind of have a hard time seeing the outcome for you of even any good examples being anything other than "eh, I can live with those few levels sacrificed".  Especially since I think that's essentially how I could justify for myself living with the elimination, and I certainly don't weight the problems of variable SI anywhere as severely as you do.

I'm not really a level designer.  I don't mind variable SI when used judiciously in level design, but I don't expect a huge loss in great levels if it is eliminated so I'm willing to live with its elimination.  Most likely the thing I'd miss most would be the act of lowering SI to finish the level and then hearing the resulting dense stream of exiting lixes--I think by years of habit I've come to associate that with the victory of successfully solving a level.   (And I guess I do worry a little about what the experience would be like to execute those solutions where we try to substitute runners for variable SI.)

[Simon]

We're in this one together is a good nontrivial example.

Spoiler

On first sight, it's a prime example for runners: Compress lems to walk through a trap. Nepster has warned explicitly against this idea, and I see first problems with runners, too. Several runner groups would have to cooperate.

The first idea is SI about 30-40, give 1 extra floater and 6 runners. Send two clusters of 3 lems through the leftmost trap. Let the trap kill 2/3 of each group. The level would lose a bit of its spirit, because one idea of the intended route is to have these groups coordinate, losing in total only 3 lems to the trap, not 4.

There is still an extremely interesting puzzle left: Bashing and bombing the solid part is a level-worthy idea on its own. You don't guess that from your inital look at the level. This seems to be the core idea. Everything else is built around it, and this core is left fully intact. But I don't want to make this call for Steve, the designer.

Change of opinion from example levels: Lower probability than 3 days ago. When I made the thread, I expected more levels to pose design problems to remain solvable, keeping their spirit. That assumption turned out wrong. Then I expected more levels to rely on it for comfort. My small personal sample suggests there are few such levels.

Nonetheless, I want to look into Nepster's list further, and meet with Icho tonight.

-- Simon

[Nepster]

I keep repeating myself, but my list of replays above is NOT a list of solutions/levels that cannot be adapted, once the possibility of these solutions is known to the level creator. The problem is, that when creating the level first, level creators will not know about such solutions and therefore won't adapt their levels to make the unkown solutions easy to execute. So most of the levels in the list above wouldn't have been designed differently if SI-changes were impossible. However the solutions mentioned above will become either very fiddly or impossible.
A prime example is Labyrinth of Despair: The replays use SI-changes to get another Lix close to a climber to bat her somewhere. The level can be very easily adapted by adding a few runners. On the other hand one can fiddle around without changing the SI to achieve the same result. In addition to that, there are solutions requiring no SI change at all. So it would have not been clear to me (would I have been the level creator) that runners should be added.

[Proxima]

There's a very clear reason not to add runners: it would make it possible for a runner-climber-jumper to clear that gap without any assistance.

[Simon]

@Nepster: So the argument is: We encourage level designers to make easy the execution of alternate accepted solutions. Variable SI is less prone to backroutes than runners, therefore the level designer is more inclined to give variable SI than extra runners.

This rests on the assumption that runners introduce more backroutes than variable SI.

There has been a Lemmings 1 level designing tradition for over 15 years, with lots of experience about what kind of backroutes come from variable SI. There is comparatively little judgement with how runners affect backroutes.

Level designers are reluctant to give runners, no matter whether they introduce backroutes or not, merely because they are a skill. The intuition is that giving extra skills is bad. This is a psychological hurdle [not always, there is something to it, see Labyrinth of Despair below], even if well motivated from Lemmings. 5 years ago, level designers have given strict time limits, just to be sure. It turned out that many weren't needed, damaged the playing experience, and designers have understood that.

Side issue: For optimizing solutions, variable SI doesn't cost anything, but runners are included in the total skill count. Whoever optimizes solutions goes through incredible pains with precision. This is independent of what tools there are; fidgeting with variable SI only adds to the pain, due to its many settings that affect very little.

@Proxima: Thanks for pointing out counterexample, will examine the level again.

-- Simon

[Nepster]

@Nepster: So the argument is:...

Yes, essentially this.
And remember that SI-changes are by default available and can be turned off when creating backroutes. Whereas runners, ... are by default not available and have to be added when needed or helpful. As the majority of levels does not have backroutes created by SI-changes (or equivalent features), I would prefer to have this available on default (similar to: Unlimited time is default, but it can be changed).

Proxima: Good point regarding Labyrinth of Despair. Completely missed this!

[Simon]

Yes, that too has been my next thought. As said to Proxima in IRC right now:

<SimonN> Nepster's argument is how variable SI helps solutions that aren't even known yet, because it is a comparatively gentle tool
<SimonN> with value for the player first, and only secondly for the designer
<SimonN> I find this the most substantial argument so far
<SimonN> and this is very hard to prove with examples, because it caters to yet-unknown solutions, especially of such open-ended levels
<SimonN> one possible answer to level designers is (give runners, unless backroute, then remove them); similar to (give unlimited time, unless backroute that is hard-to-fix otherwise, then impose time limit)
<SimonN> the problem here, which is very sad from my standpoint, is that (unlimited time is simpler than limited time), but (no runners) is simpler than (10 runners or something in every level)

Also on IRC right now: Insane Steve agrees that my impression of We're in this one together's core idea is correct, and other things are secondary to that. On the other hand, I was very direct with this special question, and haven't had let him read the entire thread so far.

Back to helping unknown solutions: Is there any method to measure how prevalent this is? What portion is affected with variable SI? Even with variable SI, people often come back to the designer and say "This is very fiddly, I hope you haven't intended this."

<SimonN> I estimate that I won't make the decision in the upcoming days
<Proxima> good, that gives me more time to formulate my thoughts
<SimonN> my hunch is that Nepster overestimates the value of VSI for the player, but I don't want to assert it, because he's done much more level design than I have

-- Simon

[namida]

Could one possible solution be to make the SI variable, but not to such fine degrees? For example, have it as a matter of "0 lix space between spawns", "1 lix space between spawns", etc?

[Simon]

I will postpone this decision for several weeks.

There is Nepster's value for unknown accepted solutions. Proxima would like to post pro-VSI arguments at some time, and I could elaborate further on game-design problems.

I've seen some levels at Icho's that use variable SI creatively and cleanly at the same time, but I've also seen levels where he could have picked a much better default SI. Variable SI for level designers is neither a pure win nor clear loss, measured in the quality of built levels.

Coarsely-variable SI (that can only take certain values) seems to combine the loss of no-variable-SI with the usability/game-design problems of variable SI. Toggling between RR 99 and the slowest-possible SI fares a bit better instead of setting a number.

I'm a little bit exhausted, because the other proponents of everywhere-fixed-SI haven't posted at all yet. Maybe it's convenient to let me do all the front-line work, but I will forget, misvalue, or misrepresent pro-fixed-SI arguments, too.

-- Simon