Very cute, and very funni x)
You can never go wrong with silly little slimes, they're peak character design in a pinch. I like the overall theming of the facility, and I appreciate the few props here and there. They might not be a lot, but they do a good job of making the place look nicer.
The music is very good, but I will admit it's also kind of hilariously "Noir" compared to the rest of the game, wich honestly can also be seen as a plus xD
I like the abilities, ceiling sticking is not something I see often and I do appreciate it here. I enjoyed quite a bit the little petit platforming gauntlets you threw here and there, in fact I wish you did more of them, your player mechanics flows really nicely for challenges like these!
Combat on the other hand is a little mindless, all I found myself doing was hitting and backing off multiple times until the enemies were dead, there wasn't much anything else I could do other than occasionally jumping with the enemies to hit them on the air too. It also felt pretty clunky, every 3 or 4 attacks my little slash just decided to not have a hitbox attached to it wich resulted in me taking hit a few times from enemies that didn't received knockback.
I also felt like the slime bosses were a little too tanky for how unengaging their fight was (All of them acts exactly like any other normal enemy) so I'm afraid they got old pretty quick.
I also took a big while to realize I could stand on top of shelves and doorframes, I would make these look more alike the other darker phase-throught platforms to indicate that or vice-versa, making the platforms look more like the doorframes. I actually killed myself on the lava pit on the clue room to backtrack to spawn because I didn't realize I could stand on top of the shelf at the time lol
You did pretty great on the metroidvania aspect with your abilities and the map was also very fun to walk around even if it was short and simple, but there were 2 details that bothered me a little:
Firstly, the health upgrades, wich you kinda just... threw them anywhere and called it a day lol, they really don't feel like they're rewarding exploration nor skill nor anything at all, they're just kinda.... on the way. I know having minor upgrades like health ups is a metroidvania staple, but I'd rather you don't try to tackle them on if you can't or don't have the time to build some more organic spots for them.
Secondly, the big final door says "Feather required" if you try to enter it early, and later it just opens wihtout any aparent reason. I'm assuming it gets unlocked by either the dash or the double jump, but regardless wich one it is, it defeats the purpose of ability gating in the first place. You shouldn't block our way with a literal door that arbitrarily opens once you have a certain ability, you should block our path by putting said door on a platform too high to reach or on the other side of a cliff faraway from us.
I guess that's it for today, thanks for coming to my Ted Talk, and also thanks for submitting! Hope you had fun participating x)