Backpack

The backpack doubles your ammo-carrying capacity, letting you carry up to 400 bullets, 100 shotgun shells, 100 rockets, and 600 plasma cells at once. It contains 10 bullets, 4 shotgun shells, 1 rocket, and 20 cells when you pick it up (20, 8, 2 and 40 on I'm Too Young To Die).

Stats for IWADs

Game	ITYTD and HNTR	HMP	UV and NM
Ultimate Doom	28	28	28
Doom II	48	48	48
TNT: Evilution	31	32	32
Plutonia	33	33	33