The Rayman 1 (Jaguar) engine is an unnamed 2D engine originally developed by Frédéric Houde for the Atari Jaguar version of Rayman 1. It was written in Assembly and based on the structure of the engine for the cancelled SNES prototype. The other versions of the game use a separate engine with multi-platform support.
Not much is known about the history of the engine. It was only ever used for Rayman 1 and there are only 3 dumped ROMs of the game, 2 of which are early prototypes. Although these prototypes are very early builds of the game the general structure of the engine would still stay the same for the final game.