A very important part of Lost Planet 2 is upgrading your character and getting more powerful weapons. During the game killing certain enemies leaves behind a box in place of, or along with T-ENG. You get to open those [?] boxes and see what you’ve collected when you see your Episode stats.
[?] Boxes are awarded in LP2 notably after killing Akrid bosses, and some smaller Akrid, plus for other enemies and after performing certain tasks. Collect the boxes by running over them, or “shooting” them with your anchor.