Ok, a few notes, this doesn't address everything mentioned in this thread by far, I'll comment more at some point.
First off, looking at the poll results, and with the announcement of Project Capybara meaning that not all levels that don't fit in here have to be scrapped, I'm now confident in picking 240 levels as a total. It also means that rather than leaving out the not so good levels, I can also consider diversity in my picks.
Note that I'll probably want to go down to 236 or 237 so I can add a few levels to the Simple rating to smoothen the difficulty curve.
The following are pairs of levels that are kinda similar. I would want to move on of them each over to Project Capybara, but only if there's guarantee that they really will be used there because I don't want to see them scrapped (with maybe the exception of "When the Levee Breaks"/"Castles in the Sky").
Either "Absolute Zero" or "Eye of the Needle". I think knowing the solution to one of them makes finding the solution to the second significantly easier. I think "Absolute Zero" is harder so I'd pick that one to keep.
Either "Don't catch me if you can" or "Top Gear". Both are built around a similar main trick, they are a bit more different than the previous pair though, so I'm not 100% confident here. NaOH said "Top Gear" seemed too easy for Hopeless, so I'd keep "Don't Catch me".
Either "Over the Hump" or "Lixes in Motion". I'd probably roll a die here for the decision.
Either "When the Levee Breaks" or "Castles in the Sky". Two execution levels of similar difficulty, so I only want one of them. Inclined to keep "Castles in the Sky" for author diversity even though I find it a bit more annoying than the other one, but I'm not sure here.
"Dances with Lixes" (if I can't enforce my solution, I will ponder this), "100% Built by Lixes" and "Ascending and Descending" are all very similar in spirit, and I'd only want to keep two of them. "Ascending" is in Hopeless, "100% Built" is by ccx which is especially a reason against moving if I already move "Top Gear", but difficulty-wise the level being close to "Ascending" might be a reason in favour. I don't know. EDIT: Here's yet another version of "Dances with Lixes" which I think enforces my solution? Not 100% sure though. Wonder if adding a blocker to ease execution would introduce backroutes as well. Please check out this version and tell me what you think.
More levels that I don't want to see scrapped but rather appear in Project Capybara:
Heavenly Skies, The Giant Mushroom - So I don't have to worry about prettifying it for now.
A fearful symmetry - Now there are two different levels of that name. The second got submitted really late, the first needs a rename. I'd just move both to Project Capybara to make things simpler for myself.
Levels that I will very likely move out, in part by request, and I don't insist on them ending up in Project Capybara:
Confusing Fractals
Snake
Wrong Way
A Lix on the Edge!
Play Ball!
Diggin' The Air
Bibbidi-Bobbidi-Boo
It's All Uphill From Here
Leap of the Locust
Levels that I will keep:
Tribute to Flagpole Sitting: Except for the looks, it's completely different from Minimalism, and very open-ended.
Fear of Heights: I think it's a cool very basic puzzle.
Soaring, Bulldozer: Again, a diversity thing as these are pretty unique.
I'm inclined to keep Three Days of the Condor as it uses a trick that is needed a lot later, and I'm not sure whether a player would stumble across it by accident.
Other comments:
I agree that "Finale" could maybe be moved down to Vicious, I had a lot of trouble with it the first time around, but I had another look today and solved it in less than 5 minutes without remembering any details about how I'd done it before. If, due to possibly moving two levels out from Hopeless (see above) Hopeless falls short one or two levels, maybe "Empty Space" could be moved up instead? And I also have finally made another level that I've been wanting to make for ages, but at some point I thought it was infeasible but now with a few changes I got it to work. It's supposed to be late Hopeless difficulty-wise, but hard to judge for me. If people like it and there turns out to be a shortage of Hopeless-worthy levels, I might consider including it, though otherwise it's a pretty late submission for that even if it's been in the workings since very early on, and there are some subtleties involved in the solution. Level is attached, feedback welcome.
Lix Cannon: As I see it, to release the left crowd all the way to the right, you have to bash to the right under the steel, but high enough so the basher stops on his own. This means you have to bash right into the steel which still removes some terrain so everyone can walk to the right. Is this intended? It's somewhat strange basher behaviour, and might not work in future (though I think it will if the steel cancelling physics will be implemented the way I suggested to Simon).
I'm in support of giving 10 of each to "Escape the Pit" as well. If I recall mobius was ok with that, Nepster you too (I'd use your remade version)? I'll also change the skill set to some other early levels so the player won't get overwhelmed. I'll announce those when I post a new version. Thanks NaOH for ordering the Simple levels so far; I'll make a few changes but overall like the ordering. I reduced the save requirement to "Downpour" even further to 25 now. I think once you figure the idea execution really just needs getting it right once or twice.