Interesting game, although I thought it was good I did have some thoughts.
First the bad. I found the control scheme awkward especially when it came to points where you had to use multiple abilities in quick succession. Using the arrow keys it also puts other movement keys directly above the ability switch keys. Although I would like to have a great suggestion here, I unfortunately don't have anything especially great. Perhaps rather than providing to switch and use abilities you could use hotkeys for the abilities. You may think that is more cumbersome, I don't especially. If you made up/w jump, down/s interact, and then zxcv(space) and m,./(space) hotkeys it would really open things up. What about my my complaint about key locations, wouldn't this make it worse? Not if you select a control scheme rather than have them both be active. The controls were the main detractor for me.
The not so bad, but still not good. I agree with what others have said that the story could really use some expansion. Yes, we have what you say in your author's comments, but it doesn't come through in the game. Especially since you have a really great start point. Bringing back the colors, but the world doesn't get more vivid or beautiful as you collect colors/flames. I honestly think you could make this a really great game, you already have a ton of great elements you just need to play off of them/make use of them. Additionally. not certain if it is the level where you get the green power or the level after, but you can climb up past the exit and you go into what appears to be a secret tunnel. It turns out this is not a secret tunnel, it is a bug, and you walk out the other side and fall forever. I personally prefer expansive worlds where exploration and daring is rewarded. Finally, and speaking of the green power, it would be nice if you made some of the other powers have extra uses in gameplay or puzzles.
The good. I really like the visuals of the game as well as the mechanics. I like games where new elements are added throughout the game, and you provide that in abundance. The game ran smoothly and looked very nice. Also, even though I did end up muting the game I did like the music as well, I thought it was quite suited to the game.
Overall it was pretty good and well worth the playthrough, but it needs some improvement to be great. Keep up the good work though.
P.S. Interestingly I checked out your website and kickstarter page. It looks like although you plan to add story and polish you don't intend more than the 9 levels currently in the game? It took me less than 1/2 hour to play through this game. As far as I can tell with no options for alternative paths, collectables, or achievements this game would have little to no replay value. I mean this in the kindest possible way, unless this is for some kind of charity $15 for a 9 level game with zero replay value may make some people unaware of how small the game is .. unhappy. Take for example "The Stanley Parable" had a max price of $15, I have gotten 6.6 hours of active gameplay out of it, and it was an incredibly good game. In a sense I am even still playing it because I have 2 more years to finish an achievement.. And they added some new achievements .. so I will have to play it for an entire Tuesday (I can only assume they mean 24 hours). Just saying, you may want to reconsider the endpoint or the price point of the game.