Unless there is an official list of glitches, the term 'glitch' will always be very subjective, IMO. For example, I would consider a couple of things others would consider glitches tricks still. A possible approach for a definition could be 'behaviour the creators of the game weren't aware of'.
You guys are way overplaying the importance of glitches. I can tell you from personal experience that even when you know all the glitches you don't always remember to use them--that just happened to me on one of tseug's level for example. (Oh, and you can already see that glitch in action in one of my Lemmix challenge replays.)
I have to agree with ccexplore on that point. It is true of course, that, if you don't know the glitch for a certain level, you cannot solve it, but this is a rare case, now that most of the glitches have been revealed. (I have to admit, one of my levels is also that way, and another one was when it was new. More exactly, these were the last levels of my CustLemm packs each. One of those glitches has been revealed, and for the other one I might create a level which you could find it in.)
Therefore, the glitches are, in most cases, not the direct reason for the difficulty of a level. If they are used, they are, in most cases again, just used as a filler or help to set up something different, or they are the main trick, then the difficulty consists in the way of how to set up the glitch, which includes new uses, triggering methods or variations of a glitch.
The point is, you use tricks in exactly the same way: I could think of a couple of ways how to use the miner glitch (Havoc 10: Flow Control, 17/21), one could do the same even for simple tricks as well, e.g. you know how to create a step with basher letting him build during his stroke, right? Now, just think of some variations: Have him stop making him digger, or blocker, or even use a miner instead of the basher, or for Cheapo, have him stop automatically when he falls into a pit during his stroke.
Now, if you understand a little how the glitches work, you can do the same for those.
But then, if you hide the idea into the terrain, the level will get extremely hard, not matter if you use tricks or glitches. And that's e.g. what tseug does. For the 8 levels of his pack I solved, I can tell you, all information about the glitches used is provided in this thread. 3 - 5 (depending on your subjective view) of these 8 are definately glitch-free. You just need to know when and how to apply the tricks or glitches in which level, and that's the problem and also the key.
My guess is that even if I do told you the entire details of the game mechanics, you still would have trouble solving the levels. (No seriously, want to take me up on that?)
Well, that's kind of my point, though I'm sorry I lost my temper about it. I've been here what, two years now? If not then nearly -- and I'm still crap. I've got a bit better at designing levels, but that's not surprising considering I was only just starting when I joined the board, and it would have been hard not to improve on that.
And I kind of hoped that things would work out like the other board I belong to, the ZBB, and the people who are really good at stuff would be able to help me get better. Instead, I've been getting the feeling more and more that this place is about the good people designing levels that only they can solve. "Elitist" was the wrong word to use, and I apologise for that; I'm sure it's as much my fault as anyone's that I haven't got anywhere. I'm just wondering, now that everyone's getting excited about Lemmini and that other new program (was it called Lemmix or something?) and Cheapo is pretty much old hat, how much point there is me staying on here.....
Oh come on, everyone (at least I think) has troubles solving levels like these. I can't say much about your playing skill as I'm rather new to the Lemmings forums, but you apparently solved most of Insane Steve's levels e.g., and recently most of SeriousGamer's levels, not everyone can say having achieved that. And, you don't want to call your levels mediocre, huh? I mean, your design is one of (if not) the best, and the levels are none you solve within 5 minutes either. (I think from our conversations you know very well how much trouble they gave/give me).
I'm currently working on a top secret (ok, just kidding) Cheapo project, so, stay tuned as with the five more levels to create it might only take a few month anymore. I've been distracted from everything by anything, therefore, and the fact that school's starting again, my progress on anything is so slow. Hehe, if ccexplore hacked Cheapo again to bug-freely record and save demos for Cheapo, my progress would be somewhat speeded up.
Anyway, did you try to change Zorn's lemming to require you to get up higher already? And another thing, in the old forum I found a not-working link from you to a 'Hard.zip', is it possible to get that anyway? Finally, if you need any help on whatever, feel free to ask me whenever you want and I'll try to help.
EDIT: Shvegait just made a very good comment. Strongly agree with that.