Captain Forever is a really simple flash game, similar to asteroids but with enemy ships. The addictive part comes when you destroy and enemy ship, the parts you haven't destroyed with your gun fire float about in space and then you attach them yo your ship. As a result your ship becomes bigger and to suit, you fight bigger and bigger ships. It reminds me of flow or the first section of Spore in many ways but just set in space, with weapons and you can customize your ship in real time.
I've spent countless hours playing this game at work on the PC and I just can't get enough of it. The graphics are simple, yet nice and the sounds are simple, yet very fitting to the feel of space. Great pick up and play flash game for 5 mins or many hours.
http://www.captainforever.com/captainforever.php
