I really liked the concept but I think that you should polish the control a little. It's a very good start point and worths further development. Nice job!

Interesting concept. Nice work! I echo everyone's feedback regarding the controls. I would use the arrow keys or WASD for grow and the same in combination with another key (space?) to shrink. With some music, sound effects and graphics (although I dig the Thomas Was Alone vibe as well) this could turn into a fun little puzzle game.

Really creative vision and great execution, I would have just a few suggestions:

the controls are not very intuitive, but I think a simple way to make it a bit better would be to use the arrow keys instead of ijkl, since ijkl is such an unintuitive control scheme. There are probably ways to make it even more easy to pick up but this is my simple suggestions

and the second would be to not use red for positive things. After the first level I immediately forgot that red were jumping platforms and avoided them until like the 5th level. Its always important to use preexisting familiarities, in most games red is bad, so red should mostly be used for something that is bad (like the enemies)

But despite those complaints, great idea!

A great use of the theme applied to a platformer, your puzzles were also nicely spaced to allow the player to explore the mechanics at a good pace. Nice Work!

Super creative! The controls are a little unintuitive and I died a few times because I confused grow one direction for shrink another or whatever, but I understand that any set of controls for this game would probably take some practice. I got through all the levels and they were all enjoyable little puzzles.

Interessting way to  moove and manage your size !

My brain melt a little, it seems it can't manage to pres 2 keys to moove around xD

Nice entry, well done !