Zero Tolerance

European version

In the human version, all human enemies were replaced with aliens and blood is green instead of red.

German index

On March 31, 1995, Zero Tolerance was put on the infamous German index by the BPjS. For more information about what this means and to see a list of games sharing the same fate, take a look here: BPjS/BPjM indexed games.

Multiplayer

Aside from being one of the rare console FPS, Zero Tolerance even managed to include a PC-style multiplayer mode. Players would send a coupon away to the developers for a special link cable that would connect two Genesis units together through the second controller port. Players could then co-op through the single player levels. No other multiplayer modes were included (deathmatch, specific multiplayer levels) and forcing two televisions, two consoles, and two copies of the game was a hefty requirement. Still, a unique addition.

Public domain

'Zero Tolerance' and its unfinished unreleased sequel 'Beyond Zero Tolerance' have become part of the public domain. The developer Zyrinx has done this under the condition that they will not be modified, and only distributed in their original form (the ROM file).

This means it is legal to download, use and keep the ROMs.

References

The five playable characters are all named after members of the development team.

Information also contributed by BurningStickMan and Xoleras