Nice find, thanks for pointing it out.
Tried a few levels and gameplay is quite nice.
I hope (and suppose) the levels get longer and more complex the farther you go.
Not in the readme but mentioned in the first link s2325, F4 is for switching to (and from) fullscreen.
Edit1: dedicated thread, might be useful for future references, posting feedback and includes some custom levels to download:
http://gmc.yoyogames.com/index.php?showtopic=394248
Edit2: s2325, regarding the screenshot (3rd link) it seems remakes.org has an anti hotlinking feature. Anyway, I guess some people won't mind the resulting image
.