I feel like the actual movement should be more refined, like jumping from sliding, and general level design doesn't lend itself to being as smooth. for example, the first platform over lava in Escape 1 is impossible to jump onto without wall running, however, in my attempts, wall running almost always didn't leave me with enough time to slide to conserve momentum and then jump again. If the platform was slightly longer, there would be more space to perform smoother maneuvers. Escape 1 also had small platforms over lava, which is fine, but they're small enough to make it very frustrating to jump from one to the other because jumping doesn't jump soon enough, and you just slide into the lava. Of course, I'm not a very good player, so anyone who can slide and jump on this platform please, let me know.
Second level I sort of didn't get was Sky 0. I get using the shotgun to get up, but then the four enemies always kill me, or I use the shotgun and get blown off the platform, or hit a barrel which shoots me into the abyss. It seems unnecessarily hard for a level 0.
I also just think escape 2, with the grappling gun, was made way too easy with walls. I can ignore the entire map with grappling to walls. With that being said, I think a level like that should be entirely in a straight line, because the corner in the level didn't make sense to me movement wise.
In the controls department, mouse movement seems way too under sensitive. I pushed mine to three and it still is not as responsive as I might like from a game about speed and jumping. Jumping also seemed to not work from sliding, as I talked about above. I really want to wall run, jump off, slide, and quickly jump again as soon as I can. There's a big chance it's just me not getting the timing right though.
Things I do like are the weapons; It feels awesome to use the grenade launcher and getting an Uzi over a pistol feels gratifying because you can actually hit what you're aiming at. I don't like getting them from enemies as much, though, because the only way to kill your first enemy in each level is to slide into them. Perhaps a way to melee enemies instead of sliding would be an improvement.
That's just what I've been experiencing. I know I've said quite a bit here, but I really do enjoy the game even after only playing it for a bit. Control tweaks would make it endlessly more fun, and the game can only go up from here.