Although everything is in first person mode, it's still a blast. You choose from one of four kamikaze Marines and go all out. Your view is a little narrow, but it's still comprehendable. You can collect mappers that show where enemies are, you can duck, crawl, jump and even punch 'n' kick your enemies (doing running punches or flying kicks is so much fun. ;D). Once you're used to the controls, you'll love showing off your infantry skills and scorching alien butt. And the levels are decently mapped out, with tons of places to go. Lots of fun. And one of my favorite parts is that there are no mind-screwing puzzles, just a search-and-destroy mission. The game makes it a point that you must destroy every sign of life per level, so you'll rarely miss out on good old action.

For a first person shooter, Zero Tolerance really seems to push the Genesis to its limits as best as it can. Character ID cards look good, enemies look intimidating, weapons look well designed, and the many environments all look decent and sometimes realistic, especially the rooftop levels. Backgrounds take damage upon being shot, and flashlights seem to have that flood light effect, done very well. You can even locate your teammates' dead body if you die and choose another Marine. And it's always lovely to see blood cake the floor, walls and sometimes, ceiling when you blast a baddie.

Personally, I love absolutely every sound this game manages to spew out, ESPECIALLY the shotgun blasts. Explosions, punch/kick effects sound wonderful, and the voices are even good. The music is also fitting, and even catchy at times, being sinister at times, and action worthy on other occasions. They even went as far as to put elevator music in here, when you are operating an elevator! Always entertaining in the sound department for Zero Tolerance.

In terms of firearms, you get it all in this. From laser-sighted .44s, to automatic shotguns, to rocket launchers, pulse rifles, C4, fun with grenades, you even get to use fire extinguishers to put out fires. The flame thrower allows you to reduce the average alien into a smoking pile of roast, and if you feel like a bag of chips, you can go postal with your bare hands (and boots!). Hand-to-alien is one of my faves, as mentioned earlier. Try a running punch, punch to groin or a jump kick! Another fun thing is sometimes, when you crouch and punch/kick/shoot a dead baddie, sometimes it will fall apart. Wonderful! [Zero Tolerance is] a challenge even to the experienced gamer, but will always have you coming back for more with its ''so hard its plain fun'' approach. It's not a walk in the park, but it's possible to nuke everything in the game and live to tell about it.

The ol' Genesis sure can dish them out when it wants to, and Zero Tolerance, a game with a fitting title and a non-stop violence streak, is definitely a winner. This has been identified as a ''DOOM clone'' to some, but ZT is much more diverse and enticing than your average shooter."

First published in 1994, the game has now been released into the public domain, thanks to current copyright holder Technopop. If you like the game, also check out the unfinished sequel called Beyond Zero Tolerance, which is also now public domain.