This is a true classic of a PC game! I truly love a lot of things about this game. The invisible tutorials, the exciting gameplay made even better through the implementation of glitches like Accelerated Back Hopping make this game just feel amazing to play! I would say that two downsides that don't account for too much are that the game is a bit too long in my opinion and that the music is not very consistent. Overall an incredible achievement by Valve though!