I really dig the graphical style and the idle animations, this is a well-put-together game already. However, there's a few big problems IMHO: first, the combat is very lacking. Now, I'm not one for super complicated controls in a platformer but combat is clearly intended to be a big part of your game - as such, I'd recommend a greater variety of weapons and a greater variety of "moves", so to speak. I also think the combat would benefit heavily from a block and/or parry control - when you're getting swarmed by enemies, timing a jump to avoid one attack usually means landing directly in the path of another. This leads to another issue: there's a TON of enemies. This may just be a personal preference of mine, but it seemed like the balance between platforming and fighting was weighted SUPER heavily in the fighting direction; this meant either taking extended breaks from platforming to deal with heavy combat situations or simply leaping over foes and bypassing the combat entirely. If you're looking for an action-heavy platformer, I'd consider ways to keep the combat less frequent but compelling rather than constant and tedious. As a last note - I'm not sure if the super dark areas are just unfinished or if they're intended to be jet black, but with the dark color scheme and the black platforms it becomes very difficult to discern what's ground and what isn't. This could be interesting in a slower-paced part of the game, but when you're getting assaulted left and right by skeletons it's important to see exactly where your escape route is.
tl;dr fantastic start and I can't wait to see where it goes next, there's just some room for improvement in the level design and mechanics.