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