You can take a few hits, so don’t stress too much if you really can’t avoid something. On the other hand, you can only take a few, so don’t get too careless.
Energy crackers and other drops will disappear if you don’t pick them up soon enough. The crackers individually aren’t valuable, but it’s worth taking a risk to grab a power-up.
If you’re having trouble handling ground-based enemies, you may want to switch to a different control scheme to make jumping easier.
It’s more important to avoid a hit than it is to defeat an enemy. There are always more enemies to shoot, but you’ve only got one life to live.
Watch out for kamikaze attacks. Some of the enemies will charge into the ground, and you don’t want to be in their way when they do.
Know your enemies. Each type of alien behaves in different ways. Knowing what kind of patterns they use is the tactical advantage you need to survive.
You don’t have to shoot asteroids to get the energy crackers within. When they crash into the ground, they’ll often leave their tasty drops behind.
The fireball power-up is great for taking out ground-based enemies, but you can also just jump on them in most cases. Just be careful, as not all of them are vulnerable to your stomping.
If you see a UFO fly by, try to destroy it. It will drop a really useful power-up that will give you serious destructive power for a short time.
Watch out for things that explode. That should go without saying, but you know how video games can be. Exploding basketballs can be kicked at enemies to hurt them, but if they explode near you, you will take damage.
Complete the missions the aliens give you to earn some bonus energy crackers. It’s worth the effort because they usually give you quite a few for your trouble.