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