Here is the full list of all 70 Serious Sam HD: The Second Encounter achievements.
Find all secrets in single player.
Complete the game in single player on serious difficulty.
Complete The Grand Cathedral level on serious difficulty without dying or loading.
Win one Team Deathmatch with at least 2 players on each team.
Win 100 Team Deathmatches with at least 2 players on each team.
Win one My Burden match with at least 3 players.
Win 100 My Burden matches with at least 3 players.
Win one round in Last Man Standing game with at least 4 players.
Win 100 Last Man Standing matches with at least 4 players.
Win 100 Instant Kill matches.
Frag 10 players without being killed in at least 4 player Instant Kill match.
Score a total of 100 points in CTF matches.
Win a CTF match with at least 2 players on each team.
Win 25 CTF matches with at least 2 players on each team.
Complete a Deathmatch with frag limit set to at least 200. (Frag limit must be reached!)
Win a Deathmatch Marathon.
Frag 25 players with a knife while having no more than 10 health left.
Frag 100 different players.
Win an at least 4 player Deathmatch by reaching frag limit of at least 25 without dying.
Win 25 1-on-1 Deathmatches.
Win 1000 Deathmatch games.
Win 100 deathmatch games.
Complete 100 Deathmatches.
Win 100 Last Team Standing matches with at least 2 players on each team.
Win a Beast Hunt match on any level.
Win a Beast Hunt match on all game levels.
Frag the same player 5 times in a row in at least 4 player match.
Earn at least a bronze medal on any level in cooperative Survival.
Earn gold medals on all Survival levels in cooperative Survival.
Hold the Burden for at least 10 minutes in My Burden match with at least 3 players.
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.
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.
Frag 100 players with a knife.
Frag 100 players in a knife-to-knife fight.
Frag 100 players with a knife from behind.
Frag a total of 100 players.
Frag a total of 500 players.
Frag a total of 1000 players.
Frag a total of 1337 players.
Complete a Coin-op cooperative game on normal or higher difficulty.
Pick up at least 10 extra life items in Cooperative Coin-op game.
Pick up 100 gold coins in Coin-op Cooperative game.
Earn gold medals on all Survival levels in single player Survival.
Accumulate a total of 100,001 enemy kills and frags combined.
Find all 3 Cannons in Teotihuacan - The City of the Gods.
Complete any level in at least 3 player cooperative game.
Find a secret under water.
Make at least 3 kills in one Instant Kill match.
Frag the same player 10 times during a single round in at least 4 player match.
Complete a deathmatch game with at least 1 frag.
Win a Deathmatch.
Earn a round for your team in Last Team Standing game with at least 2 players on each team.
Earn at least a bronze medal on any level in single player Survival.
Complete the game.
Complete the game in single player by beating estimated time on each level.
Complete the Medieval episode in single player or cooperative.
Deliver the final blow to Mordekai with the Knife.
Find at least 80 secrets in single player.
Complete the Persia episode in single player or cooperative.
Kill 100 Harpies with the Sniper rifle.
Complete the South America episode in single player or cooperative.
Burn 500 enemies to death.
Get all 3 Rocket launchers in Palenque - Sierra de Chiapas.
Perform 100 rocket jumps.
Kill 300 Kleers with the Cannon.
Kill 1000 enemies with the Laser gun.
Kill 50 Syrian Werebulls with a knife.
Complete any level in single player.