Hey man, that's a really good feedback :) thanks a lot.
We are definitely thinking to bring it to mobile platforms and therefore redesign it with a different, more intuitive, input system.
On the last level, I get your point. However, to pass the level you might cross the new marker (even though you already have that color) and then rewind to clear the cube from that color. We tried to think a mechanic that does not always require you to rewind to the 'specific' marker you took the color from, but I guess we have to think a better way to present it to the player ;)
Again, thanks a lot ;)