Unfortunately what Shrak doesn't do is provide you with a fundamentally novel plot. The online manual doesn't ive you a job description, but "space marine" would probably do the job fine. One thing I wasn't very fond of in Quake's original mission was the way the individual episodes were so easy to arbitrarily pick at will - the selection of the level was neither an integrated part of the story nor a simple menu choice (as in Doom).

Shrak does make it a part of the story - after you do the customary "choose your skill level portal" bit, you're set down in an abandoned transporter centre. At first, you can only operate a limited number of transporters, but buried within the different realms you can access are the computer parts necessary to fix more of the broken bits and get you closer to your ultimate goal, fixing up your crashed spaceship.

Along the way, however, it would be considered nice if you would rid the galaxy of the mutant threat being put together by a powerful entity known as Shrak. It seems that in the future, mankind once again created horribly powerful mutants to fight its wars, and once again those mutants went wrong and become a threat to their creators, and this Shrak fellow is harnessing all of their skewed DNA resentment.

Be Prepared
Shrak completely reworks the Quake weapon system, and adds a couple of novelties whose time has definitely come in the world of 3D gaming. The usual range of power is represented, from pea-shooter to ICBM, but the two interesting exceptions are the "Inflator" and "Friend-Maker".

The Inflator is a small dart gun which, if it hits its target, releases supercompressed gas into the bloodstream of the target. In theory, the target will bloat up, float up into the air, and explode in a gooey mess. It's only good for use at short range because it's so hard to aim, and some creatures are immune or require multiple hits.

The Friend Maker strikes me as something which would have fit well in the comic-book style of Duke Nukem 3D. It releases a neural pulse which, for some targets, will turn them over to your side and kill as many of their former allies as they can until they're killed.

Very handy, but difficult to use effectively in a firefight, because you take a real risk that it won't work and while you're trying to convert them, they're trying to blow you away.

You also have a "utility belt" with some dandy accessories. The launchable proximity mine is quite nice (although it gets to be easy to bow yourself up if you're not careful - the mines don't discriminate), but the other two are the real gems.

Finally, a hero who has planned ahead for the sorts of things hero's often have to do - climb difficult heights, and get around in the dark, Shrak gives you a grappling hook and rope, and flares which you can use to light up dark corridors. The flames are the best, most obvious, solution to the "dim light for dramatic effect vs. actually being able to see the enemy" debate that always goes on in these 3D shooters.

Probably the best new monster in Shrak is the nasty eyeball which chases you around shooting lightning bolts. The killer is, after you've dispatched the eyeball, the remains stay electrically charged for a while, and can actually do more damage while you're trying to get past than when the eye was alive.

Shrak attempts to set atmosphere not just through action and new sound effects and music but with "room descriptions" that appear at the top of the screen. They're not used as often as they might have been though - they do a good job of setting up action at the beginning of the game but I was hoping for more.

The designers probably thought it slowed down the pace too much to force the player to sit and read too many, but a few more of the sort letting me know that I see all sorts of alien life forms on my scanner in the room just through that door could have gone a long way.

The level designs are in general quite solid. The underwater action is more merciful than in Quake, not requiring as many feats of blurry-eyed navigation through muck and slime (although there is more of that), and you don't get the feeling too often that you're deliberately being kept from reaching the next level just to prolong the game.

Since the vast majority of Quake add-ons are focused on deathmatches, it's a rare treat to get a coherent story for single player action, and even rarer to get one that's actually quite fun to play.