When playing the AstroPop game in the Xbox Live Arcade demo section, you can obtain unlimited play as the default "unlocked" character. When you reach level 3, you will be asked if you want to continue or purchase the game. Continue normally or press [Back].

Both choices will let you continue playing. However, when you come to the next "demo checkpoint", which should be the beginning or end of level 7, you will get this question again. Normally, you are only permitted to purchase the game. However, if you press [Back], you will be permitted to continue playing (up to 10,000,000+ points and at least level 46).

You can play as far as you are capable and attain much higher scores. You will also get to see the new colored blocks that are introduced, etc. Once you "die", you will get a final statistical screen like any other demo session, and can do it all over again.