Wow. The game is amazing. I have nothing negative to say about it.
There are loads and loads of game mechanics which get gradually introduced, the difficulty slowly increases (easy in the beginning, pretty hard in the later levels), I absolutely adore the art style, and since it's a bit dark, the colours nicely stand out. There are also collectables which reward those who take risks, controller support etc. I even accidentally noticed you can change the colour of the main character! Cool! The level design is superb, too.
It would take *long* to list everything I enjoyed about the game.
I didn't finish it, though, because despite reaching multiple checkpoints, the continue button didn't work after Game Over. If that's what is supposed to happen, then what is the point of the flags anyway? Only to load the game if you quit mid-way through?
This is perhaps my only true complaint.
As for the minor stuff:
– The keyboard is set up for the French layout – ZQSD, correct? I'd perhaps add an option to switch to the much more common WASD. Luckily, you can use arrow keys, too.
– Level names look like they've been pulled straight out of the game files ("wood_11", "night_4" etc.). Does the underscore make it look better? I'd say it'd be better without it, but that's up to you.
– Sometimes the art style is inconsistent, as in some objects' pixels are larger than others. The breakable platform seems slightly out of place to me (in comparison with the rest of the environment)
– The game over screen shows the base blue colour, not your actual one (e.g. if you change your colour to red, the game over screen probably ought to reflect that and show a red face)
– You could also try adding medals to make the game even more popular:
http://www.newgrounds.io/get-started/
Once more – great job! Well done and welcome to Newgrounds.