i'm not able to make the game speed up without just changing the game frame-per-second value, which can't (as far as i know) be dynamically set. The slow-down works by freezing intervals of game frames, so there's not a process for doing this in reverse, as 'normal speed' is already at 100% frames running.
also, is there something wrong that's making you have to play a x1 screen? is the window resizing not working?