I'd also prefer Saturday. Sunday might be possible, but can't say for sure.

Anyone interested in playing tomorrow?

I'd also be up for Ultimate Chicken Horse instead.

I'm not free the coming weekend.

Regarding glitches, I'm fine with whatever rules; even anything goes is fine with me (I barely know any glitches anyway).

If you want glitchless, I think most cases are pretty clear-cut, but there's always little corner cases. Same in Lemmings. What is common sense? I remember long time ago it wasn't clear whether turning a digger with a blocker is a glitch or trick. What is "against the spirit" of the game? Are backroutes in Lemmings against the spirit?
That said, I don't really care, I'm not that good anyway. If everyone goes by their own common sense then things probably mostly align and anyone who's not super competitive will be fine (anyone who is considering using anything in particular unsure about could just ask what people think). There's also useless minor glitches one might trigger by accident (e.g. sprite glitches like jumping up next to a button somewhere in Labyrinth zone makes you jump in the walking sprite), I'm sure you don't want to disqualify people for that. So yeah, I'm not too serious about having clear rules here as I don't really care about the results that much.

Either way, if we start with Sonic 1 Simon posted the rules for the glitchless category.
So these could just serve as our rules, if we need that. Maybe you also want to take out going over the top of the level in Spring Yard?

I'd be interested in such a race, might be difficult to schedule across timezones though with me being away on weekends quite often. I only know S1, S2, S3K and Sonic CD (played through Sonic Mania once, but don't have any recording set up on Windows).

Fixing a character in advance seems to make sense to me (in S3K then there's also the question if it's Sonic, should it be Sonic+Tails and if so, can you have input on the second controller to e.g. lift up Sonic through the level? Probably not). Glitches are heavily abused in the runs, but then (I presume?) we're amateurs and most of them are too tough to learn quickly and pull off reliably anyway, so trying them in a run would be more of a gamble than a sure advantage, which can be fun too. (I think in past S3K races even between pros skipping a bunch of glitches was often the better strategy in the end than being stuck trying to pull of a glitch). And I'm pretty sure any of us would lose clearly to the pros in a glitchless run as well, unless I'm underestimating you guys.

Surprisingly for such a small level, Forestidia's solution is a backroute (which might have made it more fiddly than necessary). I'll fix it by increasing the spawn interval a little and post an update. Nepster's solution is intended, modulo a minor difference which I don't care too much about.
Icho's solutions are the same as the Forestidia's and Nepster's solution.

I've solved Proxima's level. Wasn't immediately obvious (also, the fall looks a bit like a splat fall due to the large zoom), but I managed. Nice one.

That's almost entirely intended, all the main ideas are in there.
I made a couple of changes, fixing your old backroute, and also enforcing the last bit of my solution. I also made a few tiny tweaks that should make execution a little bit easier (but not much). It might still take a couple of tries to get the timing right, but the title might help with that.

I'll be travelling for the next 4.5 months from tonight, so I don't know how frequently I'll check the forums.
While I'm in Ethiopia (first 3 weeks) and Spain (1 week) probably not at all, while I'll have to see how my internship in the US (last 3.5 months) goes.
So send any moderation requests etc to the other admins/mods.

btw if anyone lives in the Bay area California, we could consider meeting up at some point.