You have to shoot aliens and deal with the gravity. There are seven levels to complete, with two waves of enemies each. The first one is a 'learning to fly' level and with the last ones, you'll have to fight very agressive enemies.
It's a bit difficult to take the control of the ship and it may take a while to master controls but it's worth it. Once you master controls, the real fun will begin and you'll really enjoy aerial combats.
In the final level you'll have to fight a giant worm dragon. This dragon is almost invulnerable but you can kill it by shooting in its head. Avoid to stay in front of its head, it can also shoot bullets in your direction. It is also able to launch missiles. Be patient and you'll learn to dance with the dragon before killing it.
Download version 0.12.
Alien Storm is freeware. Redistribution and use without modification is permitted.