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