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.
Perform 100 rocket jumps.
Pierce at least 10 enemies with a single cannonball.
Drown an enemy.
Complete any level in co-op.
Complete any level in single player.
Complete the game.
Complete the game in single player on serious difficulty.
Complete the game in single player by beating estimated time on each level.
Kill all enemies in Karnak in single player.
Find at least 50 secrets in single player.
Complete Metropolis level in single player on serious difficulty without loading.
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.
Complete a co-op game on serious difficulty and extra enemy strength on 400%.
Win a deathmatch.
Win 100 deathmatch games.
Win 1000 deathmatch games.
Complete 100 deathmatches.
Win 25 1-on-1 deathmatches.
Win an at least 4 player deathmatch by reaching frag limit of at least 25 without dying.
Frag a total of 100 players.
Frag a total of 500 players.
Frag a total of 1000 players.
Frag a total of 1337 players.
Frag 25 players with a knife while having no more than 10 health left.
Frag 100 players with a knife.
Frag 100 players in a knife-to-knife fight.
Frag 100 players with a knife from behind.
Frag 100 different players in deathmatch.
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.