The best review that I read about this game was from GAMESPOT, credits not mine!
You'd be hard-pressed to come up with a game that's anywhere near as intense as Serious Sam, from Croatian developer Croteam. It's an extremely fast-paced first-person shooter, featuring a great variety of weapons and monsters. It's got a good sense of humor and a distinct style, and it also boasts a very impressive 3D engine that's especially noteworthy for its ability to display a huge number of 3D characters onscreen simultaneously. Actually, the sheer numbers of foes you'll face is probably the single most remarkable thing about Serious Sam. Then again, the game has a lot of other great qualities, such as its excellent multiplayer mode, its good sound effects, and even its low retail price. It's undoubtedly a simple game at heart--but Serious Sam does an excellent job with all the core gameplay elements that are essential to any action game.
Enemies swarm from all directions...
One look at the box--it features Sam wielding a gigantic chaingun against a horde of monsters--and you'll get a pretty good idea of what the game's all about. There's some context to why the game is set around the ancient pyramids in Egypt, why Sam's facing an alien menace all by himself, and why his enemies can teleport into the vicinity without any notice. But all this is only to loosely justify the nerve-wracking action sequences in the game, as well as the consistency in the level design. The levels in Serious Sam are progressively more challenging, but most of them are very similar in their basic style. In this way, the game is reminiscent of countless classic arcade games--Asteroids, Centipede, Galaxian, and so forth--where the reward for successfully completing a stage was the opportunity to fight your way through something even more difficult. Indeed, much like in these older games, Serious Sam even tallies a score for you based on your kills. It's a rather risky approach--ever since Valve's revolutionary Half-Life in 1998, most shooters have focused on trying to justify everything about themselves, in an attempt to give you some sort of reason for all the shooting that's happening. But Serious Sam is much more straightforward, like the '80s arcade classics but also like the classic '90s first-person shooters Doom and Duke Nukem 3D. It completely succeeds in its simplicity, because the game looks great, the controls are very responsive, and the monsters are a real challenge to fight.
Serious Sam plays much like any other recent shooter, but faster. Most players will find that the default keyboard controls for movement and mouse controls for shooting and aiming are ideal. Even the weakest enemies in the game shoot fast, so you'll immediately find that quick reflexes are necessary to survive in Serious Sam. Fortunately, all of Sam's weapons are very direct--each new one you find seems bigger and stronger than the last--and you need never worry about manually reloading them, using alternate modes of fire, or anything of the sort. There's no time for these things, since you're almost always busy fending off hordes of quick, deadly monsters. Some of these will fire at you from a distance, while many will simply rush towards you. All are utterly relentless. The comical monsters in Serious Sam stand in stark contrast to the beautiful if sparse Egyptian settings in the game. Still, many of the different monsters in Serious Sam are a pleasure to battle again and again. They lunge at you so ferociously that, every time you manage to dodge them, it's a near miss.
...and the opponents come in a wide variety of shapes and sizes
Serious Sam would be nothing without its proprietary 3D engine. It renders large, wide-open spaces and indoor environments equally well, and always very smoothly on a mid-range or high-end system. Although the level architecture in Serious Sam is fairly basic--you'll quickly lose track of all the wide-open arenas you fight through--such settings are perfect for the game's large-scale confrontations. In between skirmishes, when you do get a chance to admire your surroundings, you'll notice some of the impressive details in the 3D engine. All the environments in the game are drawn using very clear, colorful texture maps that look great even when you get right up close to them. Realistic lighting effects, which are used in the game to depict different times of day among other things, make the levels more true to life. The engine also has a few unique effects, such as pools of water that reflect shimmering light onto the walls nearby. You'll be especially impressed with the sheer size of the levels. Your character runs very quickly, but you'll still feel like you're moving quite a distance to get from one end of a level to the other. And what with hundreds of bad guys standing between you and the exit, once you finally get to the end of the level, you'll feel a real sense of accomplishment.
The great number of enemies is also possible only because of the engine used to make the game. The monsters in Serious Sam aren't the most detailed in any shooter to date, but they do look fairly good and are animated smoothly. It practically goes without saying that they bleed like crazy when you shoot them. It's incredible that the game can throw dozens upon dozens of them at you at a time, with hardly any compromise in the smooth frame rate. Since many of these monsters are fast, accurate, and powerful, having to take on so many of them at once is an experience that you won't soon forget.
Serious Sam doesn't just look good. Its use of sound is effective, though the sounds themselves are fairly terse. Most all of your weapons, from your basic six-shooters on up through double-barreled shotguns, chainguns, and rocket launchers, sound about as mean as they look. You'll almost immediately learn to identify each of your enemies by the distinctive sound it makes. Oftentimes--as with the screaming kamikaze troopers who blow themselves up when they get close enough to you--you'll need to listen carefully to gauge not just how close your enemies are, but where they're coming from. The music in Serious Sam is chock-full of bass riffs that play steadily in the background, and the soundtrack picks up when you're in combat and lets off when you aren't fighting. There are a good number of different music tracks, and though you probably won't pay them too much notice in the middle of all the carnage, they're actually quite catchy and help maintain the fast pacing of the game. Sam's also got a few choice one-liners he'll say during the course of the game, which give him character and otherwise help make the levels more interesting.
Even Sam's relatively weak weapons pack a lot of punch
The levels in Serious Sam are essentially there to let you engage in its countless battles against ridiculous odds. Their design is never confusing. For the most part, you'll always know exactly where to go next, while retreating and other such tactical considerations generally aren't possible, since you usually must kill all your enemies in the area before the next part of the level even opens up. The levels are usually balanced such that, once you finish off a horde of bad guys, you'll come across an area where you can pick up ammo and health power-ups to replenish your dwindling reserves of either one. The game also uses a certain gimmick over and over in its level design: Pretty much whenever you see a bunch of health and ammo lying around, you're going to need it, because grabbing power-ups usually triggers an onslaught of monsters to head your way. Though this can become very predictable in itself--you may find yourself saving the game whenever you happen across a tempting item of some kind--there's actually enough variety in the encounters that it never really gets old, mostly because the fighting is just so much fun. Since the basic action in Serious Sam is so well done, and rewards skill and timing, don't be surprised to find yourself replaying its levels over and over. It's even better on the higher difficulty settings, which somehow manage to make the odds even less favorable and will test the mettle of even the most experienced players.
If all this weren't enough, Serious Sam also features a robust multiplayer mode. For one thing, you can have up to four players play cooperatively or against each other on a single computer, using a split-screen mode. This won't be practical for most players, but it is still suggestive of the power of the game's engine, which readily handles the multiple simultaneous views. Otherwise the game has a built-in player-matching feature, and with it you can already find plenty of Serious Sam servers running on the Internet. Serious Sam is fast and stable over the Internet, and while the deathmatch modes can be fun, going through the single-player levels cooperatively with other live players is especially enjoyable. The game offers a very amusing selection of character models to choose from for multiplayer, all of which are like Serious Sam rejects: guys like Pirate Pete, Hilarious Harry, and so on.
You'll need to learn which guns work best in which situations
It's also worth pointing out that Serious Sam even comes packaged with proprietary level editing and 3D modeling tools for those players who're interested in building on the game's great foundation. Given how enjoyable the game is, and given that it retails for less than $20, there's no question that it'll spawn countless player-made maps, character models, and modes of play, extending the game's already impressive replay value indefinitely.
Serious Sam is essentially perfect for what it is. It's a great looking, fun-filled game that has plenty of visceral thrills and absolutely, positively the biggest battles in any shooter to date. Its single-player mode has a lot of depth thanks to the numerous secrets hidden in each level and the different difficulty options available. And the game's multiplayer mode, especially the cooperative option, rivals that of the most popular shooters available. Serious Sam may not suit those players who prefer more deliberate, more story-driven, or otherwise more serious first-person games such as Thief: The Dark Project or Deus Ex; but even these players owe it to themselves to give the game a try. Ultimately, Serious Sam is a clear lesson in what elements are necessary to make a game enjoyable. It's an unquestionably fun game from an unquestionably talented development team.