Get a high score and enter "ALF" for your name. Now you will have unlimited lives. If you manage to reach level 10, you're better off using your radar to kill the Xybots. Just line them up using radar and fire, you don't have to be able to see them. Keep as many keys with you as possible because some levels don't have enough to complete them. There are short cuts to level seven on levels one and four and you get extra cash for using them. If you have the extra energy upgrade, try not to let your energy fall below 100m, because you lose the upgrade if it does. Drums are not just for decorations, you can hide behind them when possible and use your zapper near them to find more cannon power. Near the top left hand transporter on level eight, you can get to two white coins by blasting away one of the three walls around them. Don't split up in the two-player game, because it's easier to complete it together. The master Xybot lives on level 11, and you'll need to stock up on double shot and extra shot speed to stand a chance of survival. Try to get one Xybot to stand behind another - they'll blow each other apart.