That last level was pretty damn challenging. Especially I didn't understand on my first playthrough that the waypoints slowed time so I did it real-time :D
It's a little bit sad the "waypoint" mechanic seems to be all in all mainly a slo-mo mechanic and that where they are placed doesn't really matter much (or maybe there's something I didn't understand there ?) so maybe it could have been just some kind of triggerable "bullet time" for example.
It was a good idea to play with the time with this kind of theme, however I think it was a little difficult to "feel" the ten seconds when using the waypoints as it's lacking feedback (also because using the waypoints seems to have zero limit). When playing the game real-time like I did on my first playthrough, the ten seconds mattered much more though.