Complete a co-op game on serious difficulty and extra enemy strength on 400%.
Unlocked: 18 Feb 2012 20:27:10
Complete the game in single player without firing a single bullet or shell.
Unlocked: 06 Feb 2012 11:44:19
Serious Run
15Complete the game in single player by beating estimated time on each level.
Unlocked: 06 Feb 2012 11:44:19
Co-op Hippie
10Complete The Great Pyramid in co-op with blood option set to hippie.
Unlocked: 26 Jan 2012 16:05:27
Complete any level in co-op.
Unlocked: 26 Jan 2012 15:39:27
Perfect Kill
10Kill all enemies in Karnak in single player.
Unlocked: 26 Jan 2012 15:15:12
Serious Sam
30Complete the game in single player on serious difficulty.
Unlocked: 25 Jan 2012 20:47:33
Game Master
20Complete the game.
Unlocked: 25 Jan 2012 20:47:32
Complete Metropolis level in single player on serious difficulty without loading.
Unlocked: 18 Jan 2012 18:59:00
Pierce at least 10 enemies with a single cannonball.
Unlocked: 18 Jan 2012 18:39:54
Find at least 50 secrets in single player.
Unlocked: 18 Jan 2012 09:36:36
Complete any level in single player.
Unlocked: 13 Jan 2012 10:51:55