Very good game with interesting mechanics... But I don't believe you a single second when you pretend this game was though to be impossible x). It may be a good way to bring the player to play this game though x).
Controls are a bit counter-intuitive, and need a little adaptation... I understand your choice in the button configuration, but for me, "E" is for taking objects, for exemple (since Source Engine, and even before)... I don't like either "Q" and "E" for shrinking/dematerialising, because that mean that I have to stop moving (letting the finger off "A" or "D") to do the action, and sometime I have to use them very quickly... What about shift/space (or space to jump and "E" to dematerialize) ? And, finally, I don't understand moving in the menu with arrow keyswhen moving the player is with WASD, and I would have prefered that, on the level selection, the cursor was set on the level I just quit instead of the last available... A lot of little things, but that doesn't cost more that half a star =).
What I like in this game is that there are little tricks that allows the player to do good times in time trial, and I like the leaderboard competition when a game is deep enough to allow multiple starts on a level. About that, little flaw : if you want to do a "time leaderboard" for your game, please don't round/ceil the time : show, at least, the decimals... This is way better, because it give the player more occasions to impove their time. Here, I'm like "Oh, I achieved a good time... Mmmh, I could do 0.3/0.4 seconds less, but it won't improve my score on the leaderboard... Mieh, nevermind"...
A little other thing : please, show the level number somewhere on the screen... Not only at the beginning of the level ! I want to now where I am xD !
I found a little glitch : hiting "R" twice fast (or while dying) makes you succeed the current level with the current time (0 if you do this at the begining of the level). Good to gather stars, but fortunaly, you can't submit this "0" to leaderboard.
Overall, good game with some little flaws, but I enjoyed it ! I didn't finished it yet, I admit, because I like to spend time to improve my scores on levels I achieved and find tricks to go faster and faster =) !
(Sorry for my english, I'm not a native english speaker)
~MetalFox Dioxymore