Complete the game in single player without firing a single bullet or shell.
Unlocked: 21 May 2013 14:17:03
Perfect Kill
10Kill all enemies in Karnak in single player.
Unlocked: 20 May 2013 08:51:10
Complete Metropolis level in single player on serious difficulty without loading.
Unlocked: 17 May 2013 12:43:19
Serious Run
15Complete the game in single player by beating estimated time on each level.
Unlocked: 15 May 2013 10:58:30
Find at least 50 secrets in single player.
Unlocked: 10 May 2013 09:20:06
Serious Sam
30Complete the game in single player on serious difficulty.
Unlocked: 26 Apr 2013 12:39:52
Pierce at least 10 enemies with a single cannonball.
Unlocked: 26 Apr 2013 08:22:51
Game Master
20Complete the game.
Unlocked: 11 Jun 2010 19:18:31
Complete a co-op game on serious difficulty and extra enemy strength on 400%.
Unlocked: 11 Jun 2010 19:18:31
Co-op Hippie
10Complete The Great Pyramid in co-op with blood option set to hippie.
Unlocked: 11 Jun 2010 19:18:30
Complete any level in co-op.
Unlocked: 05 Feb 2010 19:18:41
Complete any level in single player.
Unlocked: 18 Jan 2010 12:47:35