I know that you say it can be completed in 20-30 minutes, but please consider adding a save/load feature. Plenty of people for various reasons play games in smaller chunks than that. If you won't do that, you should at least have the game warn you when you go to quit that your progress will not be saved at all and you will have to start over from the very beginning.
I really enjoyed the first ten minutes of this, I'm going to enjoy them a lot less the second time if I get back around to it at all.