Here is the full list of all 70 Serious Sam HD: The Second Encounter achievements.
Accumulate a total of 100,001 enemy kills and frags combined.
Find all secrets in single player.
Complete the game in single player on serious difficulty.
Complete the game in single player by beating estimated time on each level.
Complete The Grand Cathedral level on serious difficulty without dying or loading.
Perform 100 rocket jumps.
Find at least 80 secrets in single player.
Complete any level in single player.
Kill 50 Syrian Werebulls with a knife.
Earn gold medals on all Survival levels in single player Survival.
Pick up at least 10 extra life items in Cooperative Coin-op game.
Pick up 100 gold coins in Coin-op Cooperative game.
Frag 100 different players.
Win 1000 Deathmatch games.
Deliver the final blow to Mordekai with the Knife.
Win a Beast Hunt match on all game levels.
Win 100 deathmatch games.
Complete 100 Deathmatches.
Win 25 1-on-1 Deathmatches.
Frag a total of 1337 players.
Kill 1000 enemies with the Laser gun.
Win 100 Instant Kill matches.
Earn at least a bronze medal on any level in single player Survival.
Win a Team Beast Hunt match on any level with least 2 players on each team.
Win a Team Beast Hunt match on all game levels with least 2 players on each team.
Make at least 3 kills in one Instant Kill match.
Frag 10 players without being killed in at least 4 player Instant Kill match.
Score a total of 100 points in CTF matches.
Win 100 Team Deathmatches with at least 2 players on each team.
Win one Team Deathmatch with at least 2 players on each team.
Win 25 CTF matches with at least 2 players on each team.
Win a CTF match with at least 2 players on each team.
Frag a total of 1000 players.
Win 100 Last Man Standing matches with at least 4 players.
Win one round in Last Man Standing game with at least 4 players.
Win 100 Last Team Standing matches with at least 2 players on each team.
Earn a round for your team in Last Team Standing game with at least 2 players on each team.
Kill 100 Harpies with the Sniper rifle.
Burn 500 enemies to death.
Win 100 My Burden matches with at least 3 players.
Win a Beast Hunt match on any level.
Frag a total of 500 players.
Complete a Deathmatch with frag limit set to at least 200. (Frag limit must be reached!)
Win a Deathmatch Marathon.
Earn gold medals on all Survival levels in cooperative Survival.
Earn at least a bronze medal on any level in cooperative Survival.
Complete a Coin-op cooperative game on normal or higher difficulty.
Kill 300 Kleers with the Cannon.
Find all 3 Cannons in Teotihuacan - The City of the Gods.
Get all 3 Rocket launchers in Palenque - Sierra de Chiapas.
Frag 100 players in a knife-to-knife fight.
Complete the game.
Complete the Medieval episode in single player or cooperative.
Complete the Persia episode in single player or cooperative.
Complete the South America episode in single player or cooperative.
Find a secret under water.
Complete any level in at least 3 player cooperative game.
Hold the Burden for at least 10 minutes in My Burden match with at least 3 players.
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.
Frag a total of 100 players.
Win one My Burden match with at least 3 players.
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 match.
Frag the same player 5 times in a row in at least 4 player match.
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.
Complete a deathmatch game with at least 1 frag.
Win a Deathmatch.