Trog is a 1990 maze arcade video game originally developed and published by Midway Manufacturing in North America under the "Bally/Midway" label and later by Williams Electronics in Europe. In the game, players control one of four dinosaurs chased by the titular cavemen. Its gameplay includes elements of Pac-Man—collect all items in a maze, eat a special item to turn the tables on pursuers—but supports up to four players at once. Initially envisioned as a hybrid puzzle/strategy project, its original concept was later reworked into a Pac-Man-like title after poor reception from testers and features claymation graphics, advertised as "Playmation" by Midway. Conversions for the Nintendo Entertainment System and MS-DOS were released by Acclaim Entertainment in 1990 and 1991 respectively, reducing the number of simultaneous players to two. Both the arcade and NES versions garnered positive reception from critics.
Trog is a maze game reminiscent of Pac-Man where players assume the role of Theropod-like dinosaurs (with Styracosaurus-like heads) Rex, Bloop, Spike and/or Gwen, through 49 islands set in the land of "Og", home to the one-eyed cavemen known as the "Trog" Players must pick up all colored eggs lying around the map as the titular cavemen wander around, attempting to eat them.
Unlike Pac-Man, the dinosaurs can attack at any time with a punch that does not require a power-up. The power-ups randomly spawn to help finish the level; these include red flowers that increase the player's speed; ice cubes that freeze all on-screen Trogs; pineapples, which turn the character into a full-grown T-Rex and temporarily eat Trogs (similar to Pac-Man's Power pellets, except the power-up occurs randomly); and a firebrand which bestows a temporary fire breathing ability on the dinos.
The multiplayer mode consists of two to four dinos on the same screen competing to get all of his/her same-colored eggs first, and players can either attack or protect each other (though power-ups indiscriminately hurt anyone that's in the way regardless). Many stages feature no walls, so characters can travel off the edge of the grid-like islands and plunge into the sea if they're not careful. The Trogs themselves are subject to all hazards the player is; they can even be taken out by their own wheels, fire and pits to comic effect. Trogs can be one-hit punched, to the side of the head, as they approach the screen edge, resulting in them falling into the sea, with bonus points rewarded to the player.
There are three different levels of difficulty: Easy, Advanced and Expert (Although the Arcade operator can set the difficulty in the operator menu to make the game more difficult on easier levels, without the player's knowledge of the true global difficulty.). Advanced Mode rewards a 200,000 level bonus and Expert rewards a 400,000 level bonus. As the levels progress, the cavemen become smarter and invent new ways to capture the dinosaurs. They eventually create fire pits and wheels to burn and flatten, respectively, the character and springs to bounce themselves all over the screen. Catapults and transportation chambers in latter stages help evade these attacks, however these are also usable by the Trogs resulting in some tactical gameplay options.