Serious Sam 3 Secrets

While playing the game, press ~ to display the console window, and type 'cht_bEnableCheats = 3' to enable cheat mode. Then, type one of the following case-sensitive codes at the console window and press [Enter] to activate the corresponding cheat function. Note: Codes can also be entered at the menu that appears after you press [Esc] followed by [F3]. Enabling cheat codes will prevent achievements from being earned and block your score from being posted to the leaderboards.

Successfully complete the game on the Serious difficulty to unlock the Mental difficulty.

Successfully complete the indicated task to unlock the corresponding achievement. To view your achievements and stats in Steam, select 'Community', 'My profile', 'View all my games', then the game and view stats.

Apprentice Egyptologist: Decipher an Egyptian text.
Arachnophobia: Rip 10 Juvenile spiders apart.
Are You Serious!?: Complete the game in single player on unmodified serious difficulty.
Beast Hunter: Complete a Beast Hunt match
Berserker: Kill 3 enemies in one sprint with the Sledgehammer.
Bone Crusher: Smash 20 Kleers with the Sledgehammer.
Bug Hunt: Squash 10 Hatchling spiders.
Cardiac Surgeon: Rip out 10 Rocketeer hearts.
Chain Explosion: Kill at least 5 headless kamikazes in one explosion.
Chiropractor: Break 10 Soldier necks.
Christmas In Cairo: Decorate the Christmas tree.
Circle of Death: Kill at least 3 enemies in one spinning Sledgehammer attack.
Classic Outfit: Find sam's classic outfit
Clay Pigeons: Kill 5 Cave Demons while they're in air.
Co-op Beginner: Complete any level in cooperative with at least 2 players.
Co-op Master: Complete the campaign in cooperative with at least 2 players.
Coin-op Co-op: Complete a Coin-op cooperative game on normal or higher difficulty.
Deathmatch Beginner: Complete a deathmatch game with at least 1 frag.
Deathmatch Master: Win 10 deathmatch games.
Flag Thief: Score a total of 10 points in CTF matches.
Get the hell off my ride!: Secure the bird.
Gold Rush: Pick up 100 gold coins.
Golden Survivor: Earn a gold medal in Survival.
Hammer Time: Frag 20 players with the Sledgehammer.
Headsman: Decapitate a Khnum.
Heavy Weight Champion: Win one My Burden match with at least 3 players.
Instant Killer: Make at least 3 kills in one Instant Kill match.
Killer Jewelry: Kill an enemy using the Mutilator.
Kleer Wrestler: Tear off 10 Kleer heads.
Kung-fu Fighter: Perform all possible finishing moves in the game.
Last Man Standing: Win one round in Last Man Standing game with at least 4 players.
Life Saver: Pick up at least 10 extra life items.
Load of Scrap: Rip scrapjack's head off.
Look Ma, I won!: Win a versus match.
Look, it's a secret: Find at least 50 secrets in single player.
Maintenance time: Blow a Major Biomechanoid into pieces.
Master Egyptologist: Decipher all Egyptian texts.
Mission completed: Power up the Timelock.
Old School: Complete the game in single player without manually reloading, aiming or sprinting.
Ophthalmologist: Remove 10 Gnaar eyes.
Painful Divorce: Kill a Witch-Bride of Achriman.
Problem solver: Solve the riddle of the Sphynx.
Queen Hatshepsut: Complete The Guardian of Time in single player on serious difficulty without dying or loading.
Rodeo Surfer: Use the Mutilator to surf after a Werebull.
Scorpion Slayer: Break 5 Arachnoid necks.
Serious Beginner: Complete any level in single player.
Serious Run: Complete the game in single player in half the estimated time on each level.
Serious Sam: Complete the single player campaign.
Skewer: Pierce 5 enemies with one Devastator round.
Survivor: Earn a medal in Survival.
The doorman should wear a suit: Awake the Guardian of Time.
Top Secret: Find all secrets in single player.
Trick Shot: Kill the kicked enemy while it is still in the air.
Up Close and Personal: Gib 20 enemies from close range with a shotgun.
Useful Trophy: Kill an enemy with a gib torn from another enemy.
Vista: Find the Vista secret.
Wall of Bullets: Kill 20 enemies with the Minigun without releasing the trigger.
Wanted Dead or Alive: Rescue professor Stein. So to say.