Here I explain important tricks in detail. But before that, some general tips: -dash as right as you enter the room, unless there are some reason to wait. -take sharper turns.

And now the tricks: Room1 http://ibb.co/m37Egw Dash inbetween the ceiling and the wall to save time.

Room 6 http://ibb.co/j8Zc1w Dash against this wall to land on the further corner of the platform.

Room 7 http://ibb.co/kZncZG Dash between the platform and the spikes.

Room 15 http://ibb.co/jhb4EG You could dash before hitting the floor and hit breakable wall, before hitting breakable floor. This saves like 1 frame and would be required only if you go for literally perfect run.

Room 16 http://ibb.co/bFPKgw Hit this wall while falling.

Room 17 Go fast to skip the saw.

Room 18 http://ibb.co/fGAguG The saw squeeze. You could squeeze between the saw and the wall. This requires to be pixel perfect. I could pull it off around 1/5 times. This is the hardest trick in the game, but it saves a lot of time.

Room 19 The second saw squeeze. Dash as early as you can and you could skip saws.

Room 20 http://ibb.co/mZEzEG Hit this breakable platform on your second dash. Gives you enough time to skip the saw.

Room 21 http://ibb.co/cdnh6S Jump and dash at the third breakable platform.

Room 25 Go fast to skip the saw.

Room 26 http://ibb.co/eZxKEG Dash while falling.

Room 29 http://ibb.co/j1aaMw While this platform starts to break, jump and dash to hit button earlier.