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 100 different players in deathmatch.
Frag a total of 1337 players.
Find at least 50 secrets in single player.
Complete the game in single player on serious difficulty.
Frag a total of 1000 players.
Complete a deathmatch with frag limit set to at least 200. (Frag limit must be reached!)
Win a deathmatch marathon.
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%.
Win 25 1-on-1 deathmatches.
Frag a total of 500 players.
Win 100 deathmatch games.
Frag 100 players with a knife from behind.
Complete Metropolis level in single player on serious difficulty without loading.
Kill all enemies in Karnak in single player.
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.
Perform 100 rocket jumps.
Frag 100 players in a knife-to-knife fight.
Complete 100 deathmatches.
Frag 100 players with a knife.
Frag a total of 100 players.
Frag 25 players with a knife while having no more than 10 health left.
Win an at least 4 player deathmatch by reaching frag limit of at least 25 without dying.
Frag the same player 10 times during a single round in at least 4 player deathmatch.
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.
Win a deathmatch.
Complete any level in co-op.
Drown an enemy.
Complete any level in single player.