This game is a sort of sequel/prequel to the IFComp winner "The Impossible Bottle" (TIB) by Linus Åkesson. It is an authorized sequel as Linus Åkesson selected the prize from Mathbrush which would be a game made by Mathbrush in the same universe as the winner's game. Mathbrush has done this before with success and once again it is a success.
Whereas TIB had some surreal mechanics with respect to space, The Impossible Stairs has some surreal mechanics with respect to time. Don't take the "science" too seriously. I don't think I have ever seen a story/movie/game about time travel where there were no plot holes, unless the past couldn't be changed. So don't expect a fully consistent time travel game (I don't think they exist) but a game with fun, semi-logical puzzles.
Parser:
I never noticed any parser problems. On the other hand, the game did not require an advanced parser. So it was as good as needed.
Atmosphere:
Mathbrush hits the happy-go-lucky atmosphere of TIB spot on.
Cruelty rating: Merciful
It seems that the game can never be unwinnable.
Puzzles:
The surreal logic of the first game TIB is present in this game too. This game could be completed a lot faster than TIB and the puzzles were also easier, though some of them were a bit tricky. Overall the puzzles were good.
Overall:
This game is a great sequel/prequel to TIB. Don't expect it to be as good as TIB (hardly any game is) but it is still a worthy prequel/sequel with some good, original puzzles and excellent implementation. Further more, it is written in Dialog (still only a few games are written with Dialog) and if you play online, the user interface of a dialog game is really neat.