“When in doubt, empty your magazine.” -Murphy’s Combat Laws.

Black Mesa Research Facility, New Mexico. The near future.

An experiment has caused a breach in dimensions, allowing creatures to travel from whatever realm they existed in into our world. Trapped deep in the heart of the underground facility, game players were tasked with the simple proposition: run, think, shoot, live.

That was the world of Half-Life, a role-playing shooter game from Sierra Studios and Valve. Players took on the persona of a scientist, the one who triggered the reaction that opened the portal for the creatures that killed, consumed and mutated into the form of colleagues.

Now Sierra, Valve and Gearbox Software bring more action for the gamer who craved another journey into Black Mesa in the form of Half-Life Opposing Force.

Warning, if you don’t own the original Half-Life, you can’t play this program. You also must have the jewel case for the original program containing the CD key. No key, no play. If you do have Half-Life, but haven’t bothered waiting online to update your product, don’t fret. Opposing Forces comes with the Team Fortress update and loads it in minutes. Quick and convenient.

“Don’t forget that your weapon was made by the lowest bidder.” -Murphy’s Combat Laws.

Climbing into Opposing Force is like a revisit to a nightmare. The research facility is still in shambles. The creatures are back, in seemingly larger numbers. Your job is to retake the facility. Instead of playing the role of scientist, you are a member of a select Army unit - select in that you were handpicked from boot camp and have no idea what you are getting yourself into. And the trick is in getting out alive.

Opposing Force will train you for the mission, by taking you to boot camp and letting you hone your skills. But from that point on, it is up to you and your unit. That is one of the nice new features about this program. Instead of just meandering (alright, trying to survive) about the facility as a solo act - as in the original program - in Opposing Force, you get to control a squad of soldiers. You also get a radio, which can receive messages designed to unnerve you, more than help.

The great thing about this program is the look and feel. It features a fully interactive three-dimensional environment. Yes, bullets are at a premium, but if you want to mark your path, you can actually shoot holes in the wall (as opposed to leaving a trail of bread crumbs). The game board is huge and the polygonal characters are very well rendered.

What sets this program, and the original, apart from a lot of others, is the adrenalin rush experienced when you know that there is something nasty up ahead, or in that room, and you know you have to go find it.

“If the enemy is in range, so are you.” -Murphy’s Combat Laws.

Weaponry in Opposing Force is high-end military hardware, including a M-40A1 sniper rifle. You are also given a combat vest, which is your life line in this game. Don’t let it run down.

OK, this is basically a mission pack with a bit of a new perspective, some new allies and equipment, but the same shoot ’em up, level-by-level fun. From the moment you enter Black Mesa, you know you are in for a thrilling ride.

The game is rated for Mature players (17 and older) due to animated blood and violence, and intensity.

“Anything you do can get you shot - including doing nothing.” -Murphy’s Combat Laws.

Installation: 7. Smooth and the clock allows you to know just how long it will take.

Gameplay: 8. Transitional phases are seamless, and the game board is big. You never know what is lurking around the next corner, which gives this program a nice eerie quality.

Graphics: 8. This program preserves the look and feel of the original game.

Sound: 8. Very well done.

Concept: 7. This is a mission pack. While the original game is still a solid program, this only expands that universe. It doesn’t introduce much that is new.

Difficulty: 8. There are three difficulty levels, but that doesn’t mean the easiest level isn’t hard. This game taxes brain and reflex.

Value: 9. Half-Life was a remarkable program. Because this doesn’t tax system requirements, while delivering excellent entertainment value, it is a great addition.

Overall: 7.9.