It's a dumb game with a rubbish story, BUT it's a whole lot of fun for those who have a good sense of humour.
I can't really say anything about the story because I don't know anything about it. In the game, you'll be transported to all sorts of times - Ancient Rome and Medieval times. There, you must try to escape by finding your way through areas, killing strange monsters. There's no character activity here, so Serious Sam, the character, isn't given much development. However, if you choose the Co-Op mode, you can choose different characters, though it doesn't make much of a difference.
The game-play itself is quite standard. This is just your old classic style of first person shooter. This does have a very unrealistic style though. The weapons you get are quite sci-fi. You get a weird looking rocket launcher, and a power gun, a gun that shoots out electricity. The stages the designers have put in are also a plus.
The multiplayer system is enjoyable, especially if you're versing a friend. Co-Op is quite ordinary because it's pretty much the same as normal story mode. Other multiplayer modes include capture the flag.
Though Serious Sam: Next Encounters has a shabby story, the game does manage to make you laugh, as you kill monsters in strange ways and your character cracks jokes everytime he passes something. It's basically a guilty pleasure game.