Backpack

From Doom Wiki

The backpack is a powerup that doubles the player's ammo-carrying capacity. After picking up a backpack, the player is able to carry up to 400 bullets, 100 shotgun shells, 100 rockets, and 600 plasma cells at once. The backpack also gives 10 bullets, 4 shotgun shells, 1 rocket, and 20 cells when picked up (20, 8, 2, and 40 on I'm Too Young To Die and Nightmare!).

If the player picks up a subsequent backpack, he only receives the extra ammunition. A backpack can still be picked up even when the player cannot carry any more ammo of any type.

In some Doom versions having a backpack also doubles the amount gained from picking up ammo. ^{[citation needed]}

The backpack's effect lasts until the end of the episode in Doom and until the end of the game in Doom II/Final Doom.

Using the cheat code idkfa or idfa to give the player all weapons and maximum ammunition does not give the player a backpack in vanilla Doom. The backpack is the only powerup which does not have a corresponding idbehold cheat code.

Backpacks are not included in the items percentage displayed at the end of each level.

Backpack data
Thing type	8 (decimal), 8 (hex)
Appears in	Shareware Doom Registered Doom Ultimate Doom Doom II/Final Doom
Radius	20
Sprite	BPAK
Class	Item Pickup

[edit] Appearance statistics

The IWADs contain the following numbers of backpacks:

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

[edit] See also

Doom items
Health	Health bonus | Stimpack | Medikit | Soul sphere
Armor	Armor bonus | Security armor | Combat armor
Powerup	Backpack | Berserk | Invisibility | Invulnerability | Light amp | Map | Megasphere | Rad suit
Other	Ammo | Keys | Weapons