Prehistorik Man, like its predecessor, takes place in a fictionalized Stone Age. In the middle of the night, greedy dinosaurs steal all the food from a small village. With winter coming and the village inhabitants facing starvation, the Village Chief summons Sam, a young and agile villager, and tasks him with obtaining food to help the village survive the impending winter. The player controls Sam by navigating him through a total of 23 side-scrolling levels.
The main task is for the player to collect all the food in each level while defeating enemies to make them drop their bones, which is used as currency in the game. The player starts out with three hearts. If the player loses them all, they lose a life and must restart the level. Midway through each level, there is a checkpoint (called a Rees-Tartah) so Sam will not have to start at the beginning once touched. Sam has many abilities to help the player through each level including running “like a dog” to move faster, and the shout which enables the player to defeat all enemies on screen.
Sam’s default weapon is a spiked club but he can find other weapons like spears and axes which will replace any weapon used before, however, these weapons have limited ammo. Throughout the game, various items can be found varying from “stone age shields”, which make the player temporarily invincible, heart containers to permanently raise the player’s health, and letters which spell out B-O-N-U-S, which when all are collected, send the player to a bonus area for a chance to collect more bones and food.
Shops are also available for the player to spend bones to buy various items which the player can use to skip levels or even save their game. At the end of each level, the food is tallied up and the player is given an overall percentage on how well they did. Certain levels have different gameplay gimmicks which the player must learn in order to proceed. The majority of levels are simple platformers but other levels involve the player finding specific key items, limit a player to using a vehicle, or defeating a boss.