I suddenly got a big opening of free time, since I'm in between jobs right now. This gave me the oppertunity to polish up the game mechanics quite a bit.
Since the time rewinding mechanic will probably be the main selling point of the game, I've been polishing it to perfection, step by step. The biggest lacking feature was frame interpolation.
The most difficult pieces of programming were interpolating animation states and particle systems, since these are quite complicated in Unity, but I got it all to work eventually
With the interpolation working nice and smoothly, all that remained was improving the GUI. Now evertyhing is interactable and motion trough the timline is always silky smooth. Here is an example from the game's tutorial, now with sound for the first time: