"Crash Bandicoot" has 33 levels. Two of these levels can be activated by collecting a key. Each level has a particular theme. No theme is shared by more than two levels. For example, on two levels, Crash runs toward the camera from a boulder (that is heading towards him), an allusion to Indiana Jones. On another level, henchmen throw barrels of toxic waste at Crash as he progresses toward the level's goal. There are also unlockable bonus levels by collecting three "Nitrus Brio", "Dr. Cortex" (only in 2 levels) and "Tawna" icons. These pictures are always in boxes which gives the player a reason to break open boxes since you can't save your progress unless you complete a Tawna bonus round or a Cortex bonus round. You can also save by collecting a gem.