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