a general action button is used to perform a wide range of movements in "tomb raider", such as picking up items, pulling switches, firing guns, pushing or pulling blocks, and grabbing onto ledges. items to pick up include ammo, small and large medi-packs, keys and artefacts required to complete a stage. any item that is collected is held onto in lara's inventory until it is used. throughout each stage, one or more secrets may be located. discovering these secrets is optional, and when the player has found one a tune plays. the locations of these secrets vary in difficulty to reach. the player is usually rewarded with extra items.