The presentation of this game is one of the best, is very concise, everything feel like it belongs in the game.  I really loved the art in general.

What could be better:

I felt the game needs more variety, more obstacles, enemies etc.

I love the art. Any chance of making this playable in the browser?

This is a really cute idea and I like how cohesive the art is. The controls felt a little weird to me. For example, when jumping it would be nice if I could move while still in the air. The ctrl key being the dash key made it kind of hard to reach that far while moving.

The intro music is really cool and fits the mood perfectly. 

Very cute little game! I played through what I assume to be most of it (collected the three keys and defeated the big guy, and found three abilities out of what I assume to be a maximum of 4, based on the preview images). Here are some comments on the gameplay:

• The movement takes a bit to get used to. It's interesting to play with momentum, as a standing jump has no horizontal movement, so you need a bit of horizontal speed before jumping to actually jump to the side. Unfortunately, a lot of the platforms have obstacles on their edges, making it somewhat frustrating when you keep trying to jump from one platform to the next but you bump into the ledge and all your momentum is gone.
• Very glad there was a checkpoint system! Though they could be signposted better, as I only realized the lanterns were checkpoints once I was sent back to one of them.
• The main menu buttons have an odd issue where if the mouse cursor is right above the text, the button blinks in and out.
• The "find a keys" message at the top ;)
• When I picked up the ranged attack, I received the tutorial for levitation. At this point, I already had the levitation ability. 
• Once the three keys were delivered to their place and the big guy spawned, he was stuck in place and wasn't really able to do much
• The background image appears to not be tileable vertically, there's a bit of a seam visible occasionally
• Combat is a bit hit or miss, as you just hold the attack button and try to get hits in against enemies while they walk into you and you both take damage, making it an attrition race more than anything.

Those issues aside, the visuals are really nice and the sound/music is also great! I have upgraded health and mana to 1.7 each, and found three abilities: the dash, the levitation and the ranged attack. I Assumed the game was finished after beating the big guy that shows up after the keys are placed in their stones, but I can't really tell for sure if that was the end.