Some notes I took while playing, It's all friendly suggestions, so don't read them as if I'm angery about them or anything.
-The default "use" button should be F instead of C, and the Character screen/Inventory should go to C (Which would also make sense since you know "C"haracter)
-I wish the camera didn't move while I'm fiddling with my inventory
-When dragging an item in the inventory, having which slot this item is usable on be highlighted would be very nice
-If I'm standing over more than one item and press the pickup key, everything is picked up at once, (personally) I'd rather having to press once per item, especially since the text can overlap and make it hard to read when everything is on the ground.
-Zoom-in after the last hit before leveling up is very cool, but maybe make it last just a bit less time.
-Run key feels a bit redundant. The character is plenty fast as it is, and I already have to care about a lot of other keys. Maybe just making the regular speed a bit higher, or do an automatic sprint after running outside of combat for more than 2 seconds or something like that to keep map traversal fast.
-If the potions are ONLY consumable and can't be stored in the inventory, automatic pickup could be better, although I get it if you think having to pick it up manually is better. But if that's the case do the pickup key F instead of C (please).
-After getting hit, it feels like you get invulnerability frames against the enemy that hit you, but not against other enemies, so I ended up taking like 3 hits right after being hit once. This feels really bad for this kind of game, I would heavily recommend giving at least some invulnerability frames against all enemies when getting hit. Also a visual indicator like blinking or flashing red/white to know how long that lasts. (After re-testing, something weird is happening there is flashing but it feels inconsistent because I can still take damage, I think. Again, maybe against other enemies instead of the one that hit me already)
-Basic attack consuming mana feels bad.
-Enemies colliding against each other feels a bit clunky.
-Movement speed for some enemies feels unfair and looks silly. I was being chased by a frog and he was zipping around like a racecar, way faster than its run animation would imply.
-Recovery on the basic attack feel way too long. Not only it intuitively feels like I should move way earlier, but also it increases the game difficulty in a way it isn't needed, and also feels at odds with how fast the pacing of the gameplay is otherwise.
-I feel like having a diagonal animation for my attacks instead of 4 directions only would be great, but I get that's a pain in the ass to make.
-I feel the initial area should be a safe zone and monsters shouldn't be able to follow me there.
-"Traditional" design for these kinds of games locks you in the room until you clear the enemies. I get if you intentionally want to ignore this and make it so I can freely move regardless, but I feel like some things like the teleporter should only be available/usable if I cleared the surrounding enemies. However please keep in mind I'm just thinking "out loud" and I get it if the design you have in mind is supposed to go a different route.
-The swordgirl's "Q" ability feels redundant with the Spacebar ability/dodge. (Unless it does something other than dashing that I'm missing)
-I feel like the character should be able to run past a wall when half the sprite or so is over it. I often feel like I get stuck in a corner because on little pixel on my foot is colliding with the very edge of the wall.
-The bats are very cute and the sprite is cool, but at first I thought they were like foxes or something because of the color (and because they are cute). Not really a big complain but wanted to share it nontheless
That's about it. I'm looking forwards to seeing how the game evolves. cheers!