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