If it ain't broke, don't fix it. The inspiration from portal is dripping out of this game from head to toe. The sterile test chambers, the narrator, the dark humor, the "science" it's a formula that's had it's fair share of iterations, but you've done a wonderful job with it.
Qoosh pleases not only with its quirky charm but also with its brilliant mechanics and level design. Much like portal, you have a single, simple, easily understandable tweak that allows for a massive amount of clever puzzle platforming, spread across plenty of well crafted levels.
Additionally, I appreciate the fact that you didn't baby the player with controls and whatnot. I'm reminded of Egoraptor's analysis of Megaman X in which the player was responsible to figure out the basics for themselves, instead of having them spoonfed. That sort of thing works wonders for the pacing and enjoyable difficulty curve of your game.
In short, well done, sir. Well done.