Bonus Boxes and Cargo Boxes
Bonus boxes are blue boxes found floating in most of the maps. They are free to take, and actually should be taken any chance you get. They contain loads of valuable stuff, such as ammo, credits, uridium and more. You might even be lucky and get free Gate Energy from a box. Well worth that second to stop and get them.
Also Bonus Boxes in the battlemaps (4-1 ,4-2 ,4-3) give out 1.5x what you would normally get!.
Here's a list of what you can get from a bonus box
Cargo Boxes are found floating in space when an alien or enemy ship explodes. They glow orange or gray. Gray are NOT free to take, orange are free. The contents of boxes vary in player kills, and are dependent on the alien for alien kills. The alien section of the Bible has the all the rewards for the Aliens.