The Level Design Game: 2nd Edition!

[ccexplore]

Hmm interesting.  I would think that with nuking (plus other stuff) it should become possible, if not to fully address geoo's challenge, at least to prevent the kind of unwanted solutions that both you and geoo resorted to the time limit to prevent.  Might be something for a next challenge.

I may as well show you what I came up with for a nuke solution anyway (attached). The trouble here, which I didn't consider earlier, is that adding 1, 2 or 3 extra lemmings makes the level unsolvable, but by adding 4 or any multiple of 4, without enforcing the time limit, you can just ignore the first (multiples of) 4 lemmings and use the rest to solve the level as before. What seems to be needed is some mechanism that allows a fixed number of lemmings from a given entrance through, but kills the rest (or otherwise prevents them from ever reaching the exit). This has to work without the use of any skills, otherwise (as mentioned above) you can just delay assigning the skill(s) until the right number of lemmings has passed through. Besides the time limit though, I can't imagine any mechanism that achieves this.

I think I might have finally got a way to make your level work without the time limit.

Turns out it needs some further work.  My changes introduced some new possibilities which hasn't been addressed, and also affected the method Clam used to eliminate solutions, solutions where you simply alter the timing of nuking while still using 1st lemming out as blocker.  Also, it looks like I had a mistake with the positioning of the blocker, which actually only cancels the zap trigger, without also canceling the exit trigger as intended.  Once I've fixed these problems, I'll post an updated version of the level.

[ccexplore]

Recycling the ideas from the previous level, here's my next attempt

Nice work! http://www.lemmingsforums.com/Smileys/lemmings/thumbsup.gif" alt=":thumbsup:" title="Thumbs Up" class="smiley" /> You got it this time.  I've attached my level.  now adopting a variant of Clam's naming scheme, but keeping the use of old-school 8.3 filenames (as I've typically been doing) for benefit of DOS-only users lacking long filename support

You may present your next challenge if you have one ready.

[geoo]

Ok, then here's my new challenge, which I finally got to work at the compromise of restricting the amount of lemmings to at most 40 (more than that would have become ugly with my solution):

Design a level that requires 100% to be saved with the following criterion:
For any lemming amount between 1 and 40, the level is only solvable if the lemming amount is an even number. (The save requirement is always 100%, and nothing else, including the skill count, may be altered.)

Bonus: Use fewer than 20 terrain pieces (thought behind this is that you don't set up some constuct for every pair of lemmings).

[ccexplore]

That was indeed quite tough, but I think I managed to create a level that not only satisfies your challenge, it satisfies the bonus condition and should even work for more than 40 lemmings.  The downside is that it may be the strangest looking level ever http://www.lemmingsforums.com/Smileys/lemmings/shocked.gif" alt=":o" title="Shocked" class="smiley" /> http://www.lemmingsforums.com/Smileys/lemmings/winktounge.gif" alt=";P" title="Wink-Tongue" class="smiley" /> http://www.lemmingsforums.com/Smileys/lemmings/undecided.gif" alt=":-\" title="Undecided" class="smiley" />, and needed a detailed understanding of Lemmings game mechanics to set up.

I've attached some replays (using CustLemm mechanics, though the level works fine in DosLemm mechanics too), but a detailed explanation is probably required.  See below:

The left and right halves of the level are identical, the reason for the duplication is to maximize the spacing between lemmings from one entrance, without having to set the initial RR lower than 99.

The main idea is that an upper entrance lemming requires the help of a corresponding lower entrance lemming to successfully exit.  Moreover, each upper-entrance lemming will need to execute a very particular, precise move in order to exit, but the very same move will undo the work done by the lower entrance lemming, thus requiring the same moves to be repeated for each pair of lemmings.  I will also attempt to prove later that all possible deviations from the intended solution will result in at least 1 lemming not saved.

The "(2 lem)" replay shows the basic moves in action (best viewed with just 2 lemmings).  Before we start, first note a subtle part of the terrain, circled in the included screenshot.  That "red dot" is real terrain, a lone terrain pixel on the otherwise flat surface of the steel blocks.  The basic moves involves the lower lemming bashing to remove the red dot, then walking to where the red dot was, and start building.  The build brick will be ready just in the nick of time (and extend just barely far enough) for the upper lemming to land.  The upper lemming then immediately dig.  Doing so allows him to exit immediately (ie. as soon as the frame update occurs after the digger assignment).  Without landing and digging, the upper lemming will simply fall through the exit trigger, since fallers cannot exit.  The builder will also hit the exit trigger as soon as he walks up the first build brick laid.

Notice from the replay that after the 3 moves are executed, the terrain ends up exactly the same as the initial terrain:  one pixel of the build brick remains at where the red dot used to be, the rest are removed by the digging of the upper lemming.  Thus, you need to repeat the same moves for each pair of lemmings.

Now to examine how the various deviations from the intended moves will lead to failure:

A) For the upper entrance, before the fall, steel and/or one-way walls are set up to not even allow you to assign diggers and bashers.  You can assign builders, but without the ability to assign diggers and bashers, once assigned, the builder has no choice but to move up the build brick laid, at which point he is immediately killed by the water, giving you no chance to do anything to prevent that.  The build brick that remains (which can't be removed by other lemmings due to inability to dig and bash) would also cause other lemmings to be killed by water when they walked up onto the brick.

Thus the lemmings from upper entrance have not choice but to simply walk and fall.

B) If the lower lemming do not set up a landing place for the upper lemming, the upper lemming will simply fall through the exit trigger.  Attempt to use nuke will not help in that regard, since fallers do not "oh-no", and no methods exist for an upper lemming to perform a skill while standing in mid-air (before the falling and landing).

C) After an upper lemming lands:
  i) if he doesn't immediately perform a skill, he immediately walks off the build brick and falls, missing the opportunity to exit.
 ii) Steel are set up to prevent assignment of bashers at that position
iii) You can assign him builder instead.  However, as soon as he steps up onto the build brick, he will trigger the trap object nearby the exit, resulting in at least 1 lemming killed no matter what you try.  This happens 16 frames after you assign him builder, and it so happens that the next upper lemming will land at that same time, so either you have the builder dig before he steps up, thus denying a landing place for the other upper lemming (ie. no different from if you simply dig without first build). Or, you assign some skill to the other upper lemming when he lands, which then results in death of the builder to the trap.  Replay "(kill by trap)" illustrates this happening, where I assign skill to the next upper lemming only to lose the builder at the very same frame.
 iv) So you must assign him digger as intended, and as soon as you assign digger, during the frame update he is imediately lowered and triggers the exit, denying you opportunity to assign further skills to him.
  v) I'll defer nuking to a later section......

D) For the lower entrance, similarly to the upper entrance, digger is not assignable anywhere during the walk, nor is bashing assignable in most places, and assignment of builder causes either death or exiting to the builder, interrupting your ability to create the required landing place.  Unlike the upper entrance however, there is a small section where you are able to bash (for removing the red dot), so you can certainly waste time there by having a lemming build and bash repeatedly.  However, wasting time simply denies you the ability to set up a landing place in time for the upper lemming.  (You can test this by shifting the terrain for the upper lemmings to the left by 1 pixel, so they land one frame sooner.  You'll find that they are unable to land.)

Since the landing place is needed and requires at least one builder, and you only barely have time for the basher, the only remaining deviation is to not bash.  But not bashing is a problem, because the "red dot" will still be there, and as soon as a lemming steps up on the red dot, the lemming will start exiting, denying you opportunity to assign skills to him.  The builder creating the landing place cannot clear the red dot because at his position, he can neither dig nor bash.  Upper lemmings cannot bash when they land, and their digging do not reach far enough to take out the red dot.  And the next lower lemming behind you is too far behind to be able to bash away the red dot.

Thus you have no choice but to stick to the script of bashing away the red dot, and then building at the very edge of the platform.

E) To set up the landing place for the upper lemmings, you must build at the very edge, at where the red dot is (after it is removed).  Otherwise the build brick do not protrude far enough.  You can only lay one build brick since as soon as someone (either the builder or some other lemming) steps up onto the brick, he either exits or is killed by water--either way, no further walking nor skill assignments possible to that lemming.  If you try to step up onto the red dot (without first removing it) and then build, same thing happens: you exit as soon as you step up onto the red dot, denying you opportunity to assign further skills.

So once again, no deviation from bashing away the red dot and then building at the very edge.

F) Nuke glitch doesn't help, since with 100% save percentage, use of nuke glitch simply reduces to doing the challenge with a smaller number of lemmings out.  As for use of nuking itself, since no lemmings can explode due to 100% save requirement, the only way the nuke glitch can help is to take advantage of someone "oh-no". Keep in mind also that drowning and falling lemmings explode directly without going through "oh-no".

Lower entrance lemmings are not help by becoming "oh-no", since they cannot reach any positions where they can fall directly onto an exit trigger, and as "oh-no" cannot walk or be assigned skills, an "oh-no" lemming would then be destined to explode and die.

A similar story exists for upper entrance lemmings, except once they land onto the landing place, they could theoretically fall as an "oh-no" directly onto the exit trigger.  Thus we should revisit C) in the presence of possible oh-no-ing.

Fortunately, it turns out the path from upper entrance to landing place is so short, that even if you nuke as soon as a new lemming emerges from an upper entrance (and remember, no more lemmings come out once you nuke!), his countdown is only at around 3 when he lands:
  i) walking immediately causes lemming to fall off the build brick.  Falling lemmings cannot oh-no.
 ii) Steel are set up to prevent assignment of bashers at that position.
iii) Assignment of builder is not sufficient delay to reach "oh-no".  After 16 frames, the builder would step up onto the build brick and gets killed by the trap (or some other lemming gets killed by the trap), but at countdown of 3, you will not reach "oh-no" within 15 frames, not even close.  This leaves you with the choice to assign digger before he steps up onto the build brick, which has the same effect as iv).
 iv) Assignment of digger to the lemming would immediately trigger exiting.  This cuts off further opportunities for delay and skill assignments, not to mention destroying the landing place.  Bottom line, no opportunities created for "oh-no".

Thus, having examined hopefully all possible deviations, I believe I've proved that none result in a backroute capable of saving 100%, leaving only the intended solution as desired.  I do agree though that the reasoning is somewhat complex, so feel free to scrutinize and disprove!

Finally, view the attached "(20 lem)" replay (at next post, to get around limit on number of attachments per post) to see the solution in action for the case of 20 lemmings.

I call open floor for next challenge, assuming my level is satisfactory.

[ccexplore]

I've attached a replay for the level above, for the case of 20 lemmings.

[ccexplore]

Unfortunately, having read through my lengthy reasoning above one more time, it just dawns on me that there's an unfortunate loophole that technically would render my level a failure for the challenge, in an utterly silly way http://www.lemmingsforums.com/Smileys/lemmings/sad.gif" alt=":(" title="Sad" class="smiley" />:

As noted in my explanations, use of nuke glitch reduces the level to basically a smaller number of lemmings.  Unfortunately, this means you can always solve the level, regardless of number of lemmings odd or even, by nuking right after 2 lemmings have come out.  There is enough time for you to solve the 2-lemming version before either lemming explodes or even oh-nos, thus the use of nuke glitch will allow you to "solve" the level for any number of lemmings greater than one.

Unfortunately, while typically these kinds of solutions can be prevented by lengthening the walking distance, in my particular level this is not obviously possible, but only due to the limitations the level file format imposes.  Namely, only a maximum of 16 working objects are supported.  This prevents me from adding additional water and similar other objects for lengthening the walkways for each entrance while keeping their properties the same as in current design.  Moreover, even if it were possible to lengthen the walking distance, doing so means nuking now can actually result in some lemmings reaching the "oh-no" state, which means I'd need to do more work to prove that we can't take advantage of "oh-no" lemmings to backroute the level for odd number of lemmings.

I'll leave it to geoo to decide what to do about this.  I suppose in some ways it doesn't matter too much, since I'm calling open floor anyway even if my level counts (thus it doesn't affect the next challenge).  Even if it is decided that my level fails the challenge, it is still very very close to meeting it.

In the meanwhile, I'll see if I can come up with a totally different design to geoo's challenge, though I must admit I'm feeling slightly de-motivated at this point.

[ccexplore]

On second thought, there might still be a chance to salvage my level and kill the nuke glitch solutions.  I think I can lengthen the walkways without making them exactly the same as the current setup.  If I succeed I'll post an update.

[ccexplore]

Here's my attempt to nuke-glitch-proof my original level.  A relatively simple level now turns into something a little uglier.  Following geoo's suite, I now abandon the idea of under 20 terrain pieces and only have the level worked for up to 40 lemmings, as the more lemmings to handle, the more crap I have to add to the level related to preventing the use of nuke glitch.  However, the level's main concept is same as before--it's not 20 copies of some construct for each 20 pair of lemmings.

I'm not quite as confident about backroute prevention in this version.  In fact, I'm tired and will simply shift the burden of (dis)proof to geoo and others--if you think the level can be backrouted to be solvable for some odd number of lemmings, show me!

Below's a brief summary of the change:

In lengthening the walkways to prevent nuke-glitch solutions, I simplified how the walkway restricts unwanted skill assignments.  Instead of using water to kill builders, now it's simply a very narrow walkway, where the builder will get stuck after a single build brick.  I also use huge swaths of steel areas to prevent bashing and digging in most places.  With only 40 builders now, at least for the upper walkways, you don't have enough skills to free a stuck builder.  Thus I'm reasonably confident that for the upper entrances at least, you still have no choice but to walk and fall.

The lower entrances are similar but slightly complicated by the need for bashing in one small area.   I did wind up using water and one-way-walls near the area where bashing is possible.  Even forgeting that part, you still do have enough skills to theoretically bring a lower lemming into the upper area, though I'm not convinced that would help out much.

Anyway, this is the point when I started giving up trying to logically prove that my level is backroute free. http://www.lemmingsforums.com/Smileys/lemmings/undecided.gif" alt=":-\" title="Undecided" class="smiley" />

[geoo]

I'm perfectly fine with your first level, with the nuke percentage glitch it's always a borderline case how many lemmings you consider having saved. Perhaps I should have written 'save all' instead of '100% required' in my problem statement.
For your second version, I managed to save the group of three in a level with 5 lemmings, however my solution fails on the other side with only two lemmings, as the nuke pulls one unfortunate exiter back out of the exit, thus saving only one lemming on this side. Replay attached. With your naming scheme, how do you intend to attribute a replay to its author? Adapted to it anyway, as I like the compact and monospaced pattern.
In any case, it's not a conceptual flaw to the level, and I really like your minimalistic implementation of it.
I didn't go for the neat way of having each pair of lemmings leave behind the same situation they encountered when they came, which in the end limits my solution to at most 40 lemmings, as the timing didn't work out for extending the idea to an arbitrary amount of lemmings. 19 terrain pieces used. http://www.lemmingsforums.com/Smileys/lemmings/tongue.gif" alt=":P" title="Tongue" class="smiley" />
Level and replay are attached, short sketch of the idea:

Lemmings from the left entrance will have to build immediately, as if they don't build, they'll fall to their death, or if the build later, the gap to the wall at the right will be closed, thus blocking the way.
The lemmings from the right group iteratively soften the fall so that it is barely below the max fsafe fall distance. A lemming cannot decrease the fall height by more than 1 pixel due to the timing and the trap setup.
At the end the bridge stack from the left will have the height N = amount of lemmings from the left, and the stack at the right will have (at least at the relevant point in time) the max height M = amount of lemmings from the right. If M = N (even amount of lemmings), the fall is exactly the max safe fall distance, if M < N (odd amount of lemmings), the fall is higher.

Ok, so it's open floor now!

[ccexplore]

I was working on an interesting challenge idea, but it might take a while for me to get that working. http://www.lemmingsforums.com/Smileys/lemmings/undecided.gif" alt=":-\" title="Undecided" class="smiley" />  In the meanwhile, here's a more manageable challenge, not hard but hopefully not trivial either.  (Think somewhere along the lines of my first challenge on this thread, maybe slightly harder this time.)

Design a level that satisfies the following criteria:

1) one entrance and one exit.
2) no steel
3) at least 10 lemmings
4) The number of diggers given is exactly 1.  No restrictions on other skills except to comply with the other criteria.
5) In all valid solutions to the level, the following must happen:
    i) all but 1 lemming is assigned blocker at some point in the solution
    ii) the remaining lemming is eventually assigned digger, which must be the last skill assignment in the solution
    iii) every blocker remains a blocker until freed by the digger
    iv) everyone (including the digger) makes it to the exit

To clarify on criteria #5:

a) Since the criteria must apply to all valid solutions, be on the lookout for backroutes.  This includes solutions involving nuking and blocker glitches, as well as any normal solutions using less skills than intended.  Also watch out for solutions that may be similar to your intended solution, but has certain skill assignments performed after the digger is assigned instead of before.

b) You may intersperse other skill assignments however you like, as long as all skill assignments happen before the final digger assignment.

c) no restrictions on non-skill-assignment actions like nuking and release rate changes (ie. doing them after the final digger assignment is also allowed).

[Nortaneous]

I think this works.

[ccexplore]

You've stumped me as to how to solve your level. http://www.lemmingsforums.com/Smileys/lemmings/XD.gif" alt=":XD:" title="XD" class="smiley" />  Can you double-check your level, and attach either a Lemmix replay or an English description of the solution?

Also, the level in its current form violates criteria #2, which says no steel.

[edit: it also fails criteria #1, which says 1 entrance only; your level has 2]

[ccexplore]

Okay, now that I noticed the two problems with your level, it finally occurs to me that you probably added the steel and the second entrance for testing but forgot to take them out.  I believe the level you actually intended has all the steel, and the entrance on the right half of the level, removed.

That is much closer to meeting the challenge criteria (and furthermore, is solvable http://www.lemmingsforums.com/Smileys/lemmings/winktounge.gif" alt=";P" title="Wink-Tongue" class="smiley" />).  However, it doesn't quite meet criteria #5, because it's possible to assign the floaters after instead of before assigning the digger.  Criteria #5 implies that any potential solutions where the digger is not the final skill assignment must fail to solve the level (ie. unable to meet the level's minimum save percentage).

It's too bad though, I quite like your level, and I could've easily had formulated the challenge in a different way that would've allowed and even encouraged the direction you are going with your level.  Yours is not just a level made for the sake of the challenge game, but actually a decent level to be solved, one that can belong in someone's levelset. http://www.lemmingsforums.com/Smileys/lemmings/thumbsup.gif" alt=":thumbsup:" title="Thumbs Up" class="smiley" />

[Nortaneous]

Oh wow, you're right, I completely forgot to take those out. I really need to check things before I post them... The steel was a temporary fix for a backroute that I think I solved with the gap in the floor.

It's too bad that the game doesn't allow making a lemming a builder if it overlaps with another builder. That's why I had to add the floaters.

I might try to clean that level up for a levelpack. Seems like it'd be a bit hard to not make the solution obvious, though, and I don't really like levels where the challenge is all in the execution. Especially since I can't even solve that level perfectly. http://www.lemmingsforums.com/Smileys/lemmings/tongue.gif" alt=":P" title="Tongue" class="smiley" />

[ccexplore]

It's too bad that the game doesn't allow making a lemming a builder if it overlaps with another builder. That's why I had to add the floaters.

Not sure why you think that. http://www.lemmingsforums.com/Smileys/lemmings/huh.gif" alt="???" title="Huh?" class="smiley" /> There are at least 2 ways the game allows this to happen:

1) The game automatically tries the skill assignment on a walker (more or less) if it is also highlighting a lemming already performing a skill, but that lemming cannot take on the new skill assignment.  In particular, if you have a walker overlapping with a builder, you will be able to assign the walker builder.

2) You can also explicitly ask the game to perform the skill assignment on a walker (more or less), in place of a lemming currently performing a skill (as per usual prioritization), by holding down the right mouse button while clicking with the left.  For example, say you have a walker overlapping with a digger, and you are trying to assign builder.  The game would normally assign the builder to the digger, but if you hold down the right mouse button, have the cursor highlight both lemmings, and click with the left button, the game will instead pick the walker to be assigned builder.

Moreover, unless the 2 lemmings are truly in the exact same position, you can usually carefully position the mouse cursor to only highlight one or the other.

Anyway, all the above should work in Lemmix and the various DOS Lemmings.  I don't know about Lemmini, but you shouldn't be using that for this challenge game anyway since it's based on the DOS game mechanics and not Lemmini's.

So perhaps it is possible after all to modify your level to work with my challenge?

-------------------------

I might try to clean that level up for a levelpack. Seems like it'd be a bit hard to not make the solution obvious, though

True to a point.  The reason I brought up that point is because this challenge is inspired by a somewhat notorious series of levels made by namida with the keyword "Oblivion" in the level names.  It is similar to the concept behind this challenge game, except in namida's versions, it works horizontally instead of vertically.  In both cases, it's fair to argue that given the unavoidably uneven skill distribution, it probably won't take too long for the player to realize what must be done.  On the other hand, it might still at least present some initial difficulties for very casual Lemmings players, who are more used to using one or two blockers to block off the rest of the crowd, instead of using nearly 1 blocker for every lemming.  (And to be fair to namida, in his versions at least it is more plausible for the player to attempt solutions that do not use so many blockers, so it's slightly less obvious what must be done.)

And my main point is that your level is more of a "real levelpack" kind of level than mine, which is even more stripped down, to the point where it would really seem a little silly (or at least more silly) to be included in an actual levelpack.