Backpacks serve the purpose of active items, becoming usable after a short period of time and giving additional utility to the player's loadout.

Backpack Effect
Spawns an ammo clip in the player's position which is instantly consumed while holding a gun, replenishing all ammunition.
Fires off a rapid burst with the player's weapon.
Launches Ikk high into the air. Can be used in conjunction with a double or triple jump and will count as a regular jump when used on the ground.
Creates a stationary ring of explosions around the player, damaging enemies within a certain proximity. The explosions will not reach enemies that are too close to Ikk and may damage the player if they move while activating it. Pair it with flame head to prevent the risk of damaging yourself.
Makes the player invulnerable for a short period of time, preventing them from firing any weapons and allowing them to pass through enemies.
Upon dying, the Ankh will be consumed and Ikk will be revived with the effects of death persisting; all enemies are cleared, music is muted, and the game will appear in grayscale. Music and color return after finishing the level.
Freezes all enemies for a short period of time, clearing enemy projectiles.