Pros: outstanding level and monster design, superb graphics and an epic soundtrack, very challenging and fun game in general
Cons: missing important guns to balance the gameplay: melle chainsaw, flamethrower and sniper rifle
Gameplay: even as of 2013, there is no BS side-time effects to this game. Now that a decade has past, there still has not been released a game that delivers the vast magnitude of total pwnage Serious Sam has to offer with it's immersive gameplay. Sure, Painkiller might deliver this feeling in better quality, but certainly not better quantity. You know for one, that Serious Sam is one of the most unrealistic and silly looking FPS games released - on the contrary it is his strong side. Take massive damage that would destroy a tank, replenish your health and armor with flying in the air magic pop ups, carry a barrage of weapons that only an elephant could carry, face off against the most unrealistic monsters and creatures you could have ever imagined and talk the most BS smack talk to your opponent your unwashed mouth can deliver - all this hilarious consequence works perfectly till this day since Serious Sam is still an actual and recommended game if you want just straight action and test your reflexes. The game does not have a linear feeling to it despite the fact that there are certain puzzles you have to unlock in order to progress. But achieving these puzzles will never be boring and it will feel like a non-stop acid trip. So Serious Sam indeed has puzzles, but no side quests - in order to not distract the player from anything less that main gameplay formula - kill everything that moves as fast as you can. Secret areas are present in the game, but really do not distract you - the areas are perfectly hidden and add a challenge of finding and getting them. You can replay individual levels any time you want, and once you finish a level, you get the statistics of your deeds - this makes the game very competitive for challenges like speedruns or perfect scores - just like in Quake or Painkiller.
So challenges are one of the strong points this game has to offer, and not only the chance to get some fun. Serious Sam is fairly easy if you get into it - lots of weapons to maneuver with, and the maps are overwhelmed with lots of stuff, and the only hard time you will be having is while you try to dodge a horde of monsters coming at you to maul you. Seriously, i already said that this game packs the biggest spawn count of monsters in any game ever seen, so basically hordes, throngs and swarms of monsters will come at you from all sides and your jaw will drop on the floor with thinking *** NOW!
Visuals: the game graphics are awesome, and while alot of elements look very cartoony, that does not come cheap - even these childish applications are drawn or rendered without a flaw and fit well. In contrast to all that fuz, some textures in specific levels look so brilliant and realistic, that actually feel like made in 2005. Speaking of the design - it differs, different levels and areas have different architecture and paintings. Some areas are made cheaper, some deeper, but in general you will have never seen (future perfect continuous time) such a vast caliber of well done and accurate level design and graphics. There is approach in every detail of the Egyptian building or decoration, and yet, it will not look realistic, because of the nature of the game. The game has a great level of gore and destruction, although having in mind how silly is this approached, than it is more hilarious than serious.
Soundtrack: the game features a great soundtrack, that does not annoy and fits well with the gamepaly. The music intensifies as action starts and slows down in pace when exploring.
Sound: i did not pay much attention to the in-game sounds, but it was present where it was needed and the "voicing" of the monsters and weapons is solid. One thing that is done well is Sam's trash talk, which unlike in games like Necrovision and Painkiller Overdose, does not annoy, because he does not repeat his stuff randomly... Later games tried to repeat this feature bad and it turned out lame.
Customization and menu: very rich menu and customization. Lots of adjustable things. No fault here..
Cooperative: could you ask for more? Old school games like Quake 2 and Hexen 2 had it, so why not here? Especially now that the HD edition is released, it might be a right time to establish some LAN party with a friend, pack some cold beer, and have some fun:)
All that being said, there are 2 serious flaws in this game..
Nomater how much i like this game and praise it for all it's glory, i can not be blind to the fact that Serious Sam lacks proper movement needed for this kind of fast paced shooter. All you do here is just run run run, without any innovative physics element. This is where games like Quake and Painkiller surpass Serious Sam by far.. Unfortunately this lack of innovative movement does not hurt the game that much, although i would definitely benefit it Serious Sam had strafing from Quake or air control from Painkiller. This means that Serious Sam will never fit for competitive 1 versus 1 gameplay. Another flaw in this game is a disbalance in weapons - The First Encounter does not really have a useful weapon to deal with lots of monsters at very close ranges as well as it does not have a single powerful and precise weapon to deal with strong monsters from a great distance...
The added weapons in The Second Encounter - the sniper rifle and the flamethrower DRAMATICALY change the gameplay to the better side. Certainly The Second Encounter is a better game than The First Encounter let alone judged by these weapon improvements... Anyone who scores 10 for Serious Sam The First Encounter - is simply either too biased or does not notice it's faults and their reviews will not have any critical value.
Final words: seriously, this game is the real deal, one of best action shooters ever released, an instant classic, feels totally old school and delivers the bigest and baddest fighting scenes in the gaming industry. This is a game for extreme players. I was to say that Serious Sam also features the bigest bosses in any FPS game, but that attribute goes to Painkiller (original), which is a must buy for every Serious Sam fan and the other way around. Of course having in mind you played all the old school Reven Software games before... Naturally...