Which DOS Lemmix replay did you based your video on (can you post the URL, or the topic title and reply #, if you got it from this forum)? It doesn't quite match any of the 100% solutions replay I have on my computer and I have 3. It looks closest to the one whose filename has "15builders", but your two build bridges in the video look too far apart compared to the replay. The other two replays on my computer have the bridges starting a little bit further out to the left than your video.
The solution that produces the DOS record for total skills count at 100% save, is a variation of
this one which originally uses only builders, but can be trivially modified to use 17 builders and 1 climber. It only uses very small release rate changes that are definitely doable on SNES, but as a result it takes longer for level solution to complete (nearly all lemmings are coming out at release rate 30).
The replay for the 15-builder solution is
this one, but it uses more of other skills, and so the total skill count actually comes out to 20 and not better than the DOS record for total skill count. It looks like your interest in this replay was primarily for the slightly more efficient way to hold (ie. "lock") the lemmings.
Now to address your comments:
1: If you can make this lock system working you can make 99% using 15 skills without glitches. And yeah this lock system work like DOS but releaserate is big trouble. I have to slowdown 3rd lemmings, because 2nd lemmings no have time build up and lock 3rd lemmings. Im not give up yet, but its strongly looks its requires extra builder slowdown. This look DOS version you can change releaserate when you are paused and its doesn´t work on SNES.
If you are referring to the "15-builder" DOS solution, that is not the one that produces the DOS record anyway. For the "lock system", note that you need to set the release rate to 40 before the first lemming comes out. I think you might have missed that when watching the replay, which may be why you ended up building the rightmost bridge not as close to the other bridge as you see in the replay, causing things to not work out. Release rate can be 40 at any time as long as it is before you can see the first lemming coming out. Once after the first lemming comes out, drop the release rate back to 30 before second lemming comes out. These release rate changes are definitely doable on SNES.
The 15-builder DOS solution then requires a release rate change from 30 to 67 after second lemming comes out. This can actually be made 31 to 66 for same effect. It is quite a high release rate change, but based on my calculations it might still barely be doable on SNES. Even if it isn't, it just means you have to spend an extra climber for the extra lemming that isn't part of the compressed crowd that gets slide up by the glitch. In any case, this isn't really worth discussing further because the 15-builder DOS solution is not even the DOS record when it comes to total skills.
When watching Lemmix replays, note that release rate changes have same effect regardless of exact timing, as long as it is done at some point right after Nth lemming out and right before the N+1-th lemming out--the change would then affect not lemming N+1, but the next-next one (N+2). It is not literally necessary for the release rate to make an instant jump from one value to a much larger value, though it is certainly possible with pausing on DOS Lemmings, and Lemmix replays depict all release rate changes as instant given it is always possible with pausing.
2: I finally see how this sliding glitch is maded here, but i personally not know how its exactly working. I am see it used some TAS runs and etc... But i guess its just perfect timing.
There is a brief overview
here (under section "Builders"), and I've included some additional details in below spoiler section. It does unfortunately require perfect or near-perfect timing to trigger, which means that in practice, even something as trivial as how long to let a lemming shrug before assigning him next builder, can affect the timing needed. So even when you know the exact timing details, in practice you can almost never work it out in advance, instead you need to use tools like emulators to see how much you've deviated in your current attempt from the perfect timing needed, and then make small tweaks to previous moves before the glitch to try to get the timing to line up. So I'm not 100% sure how helpful those details will be, but I guess better than nothing.
For a step height of 3 pixels (minimum), the builder needs to start laying the brick, when the lemming to be slid up is 8 pixels away from the step. The way we count the 8 pixels is: starting at the vertical column of pixels making up the step, move 8 pixel-steps horizontally away from it towards the lemming that is walking towards the step. Then line up the lemming graphics with the pixel you are at, as follows:
- If lemming is facing right, look at his face (white part) which looks like an inverted T. The left pixel of the inverted T should line up with above pixel.
- If lemming is facing left, use the center pixel of the inverted T instead.
This assumes there are no other large steps in between lemming's current location and the step, so that the lemming moves exactly one pixel forward horizontally each time game advances forward, not having to spend any extra time falling down a large step or jumping up a large step.
It actually also matters whether the builder is a lemming that comes out of entrance before or after the lemming you want to slide. The above assumes "before" (the typical case). If it is "after", you need the lemming you want to slide to be 9 rather than 8 pixels from the step.
If the step height is 4 or 5 pixels instead of 3, in additional to the timings noted above, the walking lemming can also be 1 pixel closer to step: so 7 or 8 for the "before" case, 8 or 9 for the "after" case. For step height 6 (maximum), the walking lemming can be 2 pixels closer to step, so 6-8 "before" and 7-9 "after".
Probably the most useful information is just to know what happens when you missed the perfect timing: if the builder builds too early, the step turns into a wall too early so the lemming just turns around instead of getting slid up. If the builder builds too late, then the lemmings already finishes moving up the step before the build brick is fully laid down, and often those lemmings will then get trapped in what has now become a wall instead of a step. With this information, you can tell when tweaking a solution attempt, whether you need to make the builder build slightly earlier or later, or make the lemming reaches the step earlier or later.
3: 3rd trouble is releaserate like 67 used on DOS version its not enought fast let pass 100 lemmings out fast enoought. There is 80 lemmings on DOS and 100 lemming on SNES. If you need compress you have to make it using faster releaserate or just waste more time in level.
I think you are overestimating the amount of time needed for these solutions. Testing shows that SNES advances game 15 times (steps) for the game's timer to go down one second, versus DOS's 17 times. Now let's look at the 17-builder 1-climber DOS solution, which actually takes even longer as it leaves the release rate mostly at 30:
- The level gives you 6 minutes.
- The 80th lemming comes out when timer reads 3:01.
- The last lemming to exit finishes exiting when time reads 2:18.
So the DOS solution takes no more than 3 minutes for 80th lemming to come out, which in DOS is 17 * 180 = 3060 steps. From the point of 80th lemming out to the level being done, it's about 43 seconds, let's round that up generously to another minute = 17 * 60 = 1020 steps.
At release rate of 30, there is floor((99-30)/2) + 4 = 38 steps between one lemming coming out of entrance and the next one coming out. So having 20 more lemmings on SNES would add 38 * 20 = 760 steps, waiting for them to come out at release rate 30.
Altogether we end up with 4840 steps total, which with SNES's faster game timer taking only 15 steps for each second, we end up with 4840/15 = 322.7 seconds = about 5 min 23 seconds. So yes, you are cutting it a little close, but still under the 6 minute mark.
If you're still not convinced, try this: according to the above calculations, on SNES with release rate left at 30, the 100th lemming to come out should do so around when the timer reads 1:45. Play the level doing (almost) nothing but wait for the lemmings to come out, and see how close the prediction is to reality.
There is however one trouble I've excluded: as you can see when watching the Lemmix replay, the DOS solution actually takes some time waiting after 80th lemming is out before assigning the builder that releases (ie. "unlock") the crowd. This wait is specifically to get the timing to work out later for applying the glitch. With 100 lemmings instead of 80, the required timing obviously changes, and may end up requiring more waiting (beyond just waiting for the 100th lemming to come out) compared to DOS solution. So it is possible you might run out of time as a result, only testing can tell.
As for the 15-builder solution, since it uses a comparatively higher release rate, you are in even less danger of running out of time.