ACHIEVEMENT - HOW TO UNLOCK
Serious Beginner (5 points) - Complete any level in single player.
Serious Sam (20 points) - Complete the single player campaign.
Are You Serious!? (30 points) - Complete the game in single player on unmodified serious difficulty.
Kung-fu Fighter (10 points) - Perform all possible finishing moves in the game.
Wanted Dead or Alive (10 points) - Rescue professor Stein. So to say.
Get the hell off my ride! (10 points) - Secure the bird.
Problem solver (10 points) - Solve the riddle of the Sphynx.
Mission completed (10 points) - Power up the Timelock.
The doorman should wear a suit (10 points) - Awake the Guardian of Time.
Look, it's a secret (15 points) - Find at least 50 secrets in single player.
Co-op Master (10 points) - Complete the campaign in cooperative with at least 2 players.
Killer Jewelry (5 points) - Kill an enemy using the Mutilator.
Headsman (10 points) - Decapitate a Khnum.
Chain Explosion (10 points) - Kill at least 5 headless kamikazes in one explosion.
Bone Crusher (5 points) - Smash 20 Kleers with the Sledgehammer.
Maintenance time (5 points) - Blow a Major Biomechanoid into pieces.
Trick Shot (5 points) - Kill the kicked enemy while it is still in the air.
Load of Scrap (5 points) - Rip Scrapjack's head off.
Wall of Bullets (5 points) - Kill 20 enemies with the Minigun without releasing the trigger.
Classic Outfit (10 points) - Find Sam's classic outfit.

"Jewel of the Nile" achievements
ACHIEVEMENT - HOW TO UNLOCK
Deathmatch Master (10) - Win 10 deathmatch games.
Flag Thief (10) - Score a total of 10 points in CTF matches.
Instant Killer (5) - Make at least 3 kills in one Instant Kill match.
Jewel of the Nile (20) - Complete the Jewel of The Nile single player campaign.
Look Ma, I won! (5) - Win a versus match.