Zero Tolerance—developed by Technopop, and released in 1994 (in both NA, and PAL territories)—is a doomclone for the Mega Drive, with some interesting flourishes:
The player's lives are represented by characters, each with differing abilities.
The game supports a link cable (designed by the developers), allowing two Mega Drives to be linked for multiplayer games.
There is jumping, and sloped surfaces; both unusual for the Doom-era.
The enemies are really aggressive.