I love this game, the low colour palette is great, and I like how you don't have to open a text box every time you want to read a sign, both work pretty well for a fast paced platformer.
There are a couple of things I dislike though (I know that these are mostly because it's still a WIP but I'll point them out anyway);
The walls that point to the left have an iffy hitbox on the right side, this is pretty clear here;
The death sound is annoying in a fast paced game; this is a hard platformer, and the player is going to be dying frequently: the death sound gets obnoxious very quickly. If you look at other fast-paced, hard platformers, (like Super Meat Boy, VVVVVV, The End is Nigh) they tend to have pretty quiet death sounds, or at least a sound that fits into the aesthetic of the rest of the sounds very well (like VVVVVVs sound, which while it is a bit loud, it has a similar sound to the music in the background and the jump sound, so it doesn't stand out too much).
It's a little unclear when you can wall jump; since it's such a fast-paced game anyway, it might not matter too much, but a little more clarity over when you can wall jump would be nice. Maybe a dust effect when you rub against a wall, or a small flash, something to show you're able to pull off a wall jump.
Good luck with this game, it's really fun and I like the aesthetic a lot!