The game will record your scores and keep your highest in it's best time for a single game, displaying it at the end. Here is how you can make it keep an all-time high score:
The way I recommend you play is that you just start one master game, and when you want to end the game just die/finish the round and then after it says 'Press Z to play again and press X to exit' just save, then press X to exit.
Then, whenever you want to play again, just load that game and start from there. I'll let you submit your best time to me by emailing me (email@example.com) your savegame to put on a 'Top Ten Times' list both at the downloads page and my website, m925studios.webs.com.
I've included an example of mine in the file. Don't rename that one and send it back to me. :\ I'll know.