bind key "callvote ChangeDifficulty Impossible;callvote ChangeDifficulty Easy"

Whenever you press the key it calls a vote for Expert if you're on Easy (or any other difficulty) and Easy if you're on Expert. If you don't want the vote to be on the same key you can simply separate the commands like so:

bind key "callvote ChangeDifficulty Impossible"
bind key1 "callvote ChangeDifficulty Easy"

sick, awesome to see some progress

A lot of games come with uncomfortable requirements towards certain people like requiring specific versions, hardware or stuff in general like hard tricks. Basing the "correct" version on feedback from a wide group where most people are casual and aren't interested in speedrunning the game in the first place is a rather poor way of selecting one. If older versions are available, they will most likely be used regardless of game simply because they're faster. It has always been like this. Other versions are allowed, but not recommended as they are slower.

That gets me to my point: if you really care about running the game, and don't want to get an older version of the game to be competitive; just play on whatever you have (like newest in this case). That is by far the best way to prove your agenda.

epic

There's a rather big list of things you can do in co-op and a smaller list for solo. As far as I know it's not written anywhere, so I can't really give you that accurate of an answer. A lot of the maps are changed in the latest version, patching out several shortcuts and such, with Dead Center probably being the campaign with the least changes. For tricks you cannot infinite stumble (the thing people do in solo at the start of Swamp Fever level 1). What you can do is cornerwarping, grenade boosting, grenade launcher boosting; so pretty much everything that would be used in co-op. The most noticeable changes are indeed in the maps but not really the mechanics of the game.

drop one of the mods a pm on Discord and they'll get back to you

Ah, I guess leaving it out for that reason makes sense

Don't you also need to get 100k in Normal mode (before Metsu) to get 100% completion? I feel like just having a simple checklist of things you need would make it easier to figure out what truly makes a 100% run.

So as far as I know you need to score less than 20k 6 times in Normal mode to get the bad ending, score more than 20k at least once to get the good ending, and then in Metsu mode you would need to reach level 100 after unlocking the 6 memoirs (which I'm not sure what the requirements are, but it seems to be a rather low point value) to get the final "milestone" which makes Irisu look towards you over her shoulder in the menu.

But since there's the extra collectable for reaching 100k in Normal mode I feel like it should be a part of the run as well.

Bump with more questions but since there are no 100% runs yet might as well discuss it

Inverted controls, weapon randomizer or maybe a mutation where you must protect a bot, like as a VIP or something. Not as extreme as what Sunday Driver is, but maybe they can be made harder in some way

Yeah, it isn't really a guaranteed trick. It would be nice if there were other elements to look at that don't move so aligning yourself would be an easier task. Sadly, there aren't any around that side of the tower.