Serious Sam: The First Encounter was last year's most surprising first-person shooter. Featuring a never-before-seen 3D engine that could render literally hundreds of weird, dangerous creatures simultaneously within huge environments, Serious Sam offered no shortage of pure arcade action. For good measure, the game included an extremely enjoyable cooperative multiplayer mode and a lot of good-natured humor, and the whole thing retailed for less than $20. The game was a steal, as well as a promising breakthrough for the previously unheard of Croatian developer, Croteam. Now, nearly a year after the release of the original, Croteam is back with the predictably named sequel. And while it uses the same engine, stars the same tough-as-nails wisecracking hero, and once again requires you to fight through thousands of monsters before you reach the final climactic battle, Serious Sam: The Second Encounter is not necessarily what you'd otherwise expect. It's not just more of the same--this creative, fun, extremely intense shooter is even better than the original.

The Second Encounter picks up moments after the first game left off. Having traveled back in time to ancient Egypt and defeated countless minions of the nefarious Mental, Sam "Serious" Stone has managed to hop aboard an alien spaceship that will take him straight to the heart of his archrival's domain. Unfortunately, it unceremoniously crash-lands right back on Earth, this time in South America. Like the first game, Serious Sam: The Second Encounter isn't heavy on plot. The context is really just there as an excuse to set the game within a number of colorful, exotic levels and to fill these with monsters, traps, weapons, and power-ups.

While all the levels in the first game were set in Egypt, which made them start to look pretty redundant after a while, The Second Encounter features three distinctive environments--Mesoamerica, ancient Babylon, and medieval Eastern Europe. All three are just gorgeous. Serious Sam's 3D engine creates what are certainly the most gigantic levels found in any shooter, and within each level in The Second Encounter, there's a lot of variety as you travel through both indoor and outdoor areas, both above and beneath the surface of the earth.

The game plays like the original, though the improved level design makes the action more enjoyable than before. As Sam, you can run much faster and jump higher than just about any other shooter protagonist. You can carry more than a dozen high-powered weapons and plenty of ammo for each of them. You can take a tremendous amount of punishment, and you'll find power-ups to replenish both your health and your ammo reserves throughout each level. Sam's so strong that any other first-person shooter would be a total cinch for him. But in this one, he'll be up against an impressive variety--and a truly staggering number--of fast, vicious, deadly oddball monsters. The Second Encounter provides a daunting challenge at its default difficulty setting, though it offers easier settings suitable for the faint of heart as well as tougher settings suitable for masochists.

The most obvious additions in The Second Encounter are three new weapons you can use, more than half a dozen new monsters to fight (as well as three exciting, new boss battles spread out over the game), and four new power-ups. The most precious of these power-ups works like a smart bomb from classic arcade games--when things get really bad, you can use one to frag every monster in your vicinity, no questions asked. Meanwhile, the new monsters in The Second Encounter round out the roster quite nicely. The best of them is a chainsaw-wielding maniac sporting nothing but overalls and a jack-o'-lantern instead of a head.

Make no mistake: All your favorite, and least favorite, monsters from the first game can be found in force throughout The Second Encounter, and some have a few new tricks. Old and new foes alike will attack you with reckless abandon, and as you frantically fight back, you'll feel elation mixed with anxiety--a real adrenaline rush. By mixing in the old with the new creatures and presenting all of them in a wide variety of new situations, the game succeeds in feeling substantially different from the original. That is, even if you felt exhausted by the conclusion of The First Encounter (and how could you not?), you'll be anything but bored while fighting your way through the new game.

The first game had a ton of weapons in it, but these new additions are great--there's the chainsaw, which usually isn't practical but is still fun to use (especially in multiplayer deathmatch) and a great throwback to the weapon from id Software's classic, Doom. The other two new weapons you simply cannot live without--your high-tech flamethrower becomes the single best crowd-control tool for close-quarters battles. It's visually stunning as it instantly causes everything--monsters and scenery--to ignite in flames and then to blacken to a crisp. Not to be outdone, the new high-powered sniper rifle is equally useful--its 8X magnifying scope lets you draw a bead on enemies from miles away and deliver an instant-hit, often fatal, high-caliber round. Since some monsters will bombard you from long range, the sniper rifle becomes essential for taking them out.