Thanks for your feedback!
Actually, time does not slow down nor gets faster. On the contrary, the character disappears and then re-appears some time later. The “disappearing time” is adjusted with A/D keys (not Q/D as indicated in the tutorial –sorry about that). The small yellow clock in the top-right corner indices how long the time jump will be (from 0s to 3s max).
I added a walkthrough of the 3rd level (tutorial) in the description of the game to illustrate this. Hope this helps!