All of LDW's games are designed to be open-ended, so you can play any given game as long as you like! I've had my latest Fish Tycoon game on my Pocket PC going for over a year. You can play the game many times, trying different difficulty settings and/or breeding strategies. If you're using the screen saver in the Windows version, you can change the makeup of the fish in your tanks every so often for some variety.