Full list of all 35 Serious Sam HD: The First Encounter achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Frag 100 different players in deathmatch.
Frag 25 players with a knife while having no more than 10 health left.
Frag a total of 1337 players.
Win an at least 4 player deathmatch by reaching frag limit of at least 25 without dying.
Complete a deathmatch with frag limit set to at least 200. (Frag limit must be reached!)
Win a deathmatch marathon.
Frag the same player 5 times in a row in at least 4 player deathmatch.
Frag the same player 10 times during a single round in at least 4 player deathmatch.
Perform 4 frags with each being no more than 10 seconds apart from the previous frag in at least 4 player deathmatch.
Frag all players in a single frag combo.
Win 1000 deathmatch games.
Frag a total of 1000 players.
Frag a total of 500 players.
Frag 100 players in a knife-to-knife fight.
Frag 100 players with a knife from behind.
Win 100 deathmatch games.
Frag 100 players with a knife.
Complete 100 deathmatches.
Frag a total of 100 players.
Win 25 1-on-1 deathmatches.
Complete The Great Pyramid in co-op with blood option set to hippy.
Complete a co-op game on serious difficulty and extra enemy strength on 400%.
Complete any level in co-op.
Complete the game in single player by beating estimated time on each level.
Complete the game in single player without firing a single bullet or shell.
Complete the game.
Complete the game in single player on serious difficulty.
Perform 100 rocket jumps.
Kill all enemies in Karnak in single player.
Complete Metropolis level in single player on serious difficulty without loading.
Pierce at least 10 enemies with a single cannonball.
Find at least 50 secrets in single player.
Complete any level in single player.
Drown an enemy.
Win a deathmatch.