This game is pretty fun, up until the idle donut section, where it slows down. (I didn't finish this game.) I rated the game for before that part, though.
For the action sequences (defending and mazes) the game uses the OS's settings for keyboard repeat and delay. For the next game, look at how Project Iridium works and take that - it just repeats movement on a custom interval as long as the key is pressed.
This had a big impact on how much I enjoyed the action segments, which are most of the game. Instead of holding in a direction, I had to mash arrow keys over and over, which is physically painful for me. Eventually, I just gave up and held down the keys, despite it feeling very slow and making some of the spiral mazes take a very long time.