Psycho
You killed 10 enemies without losing your weapon.
15 ✓ November 1st, 2011
Perfect Boss
You beat the first boss without dying.
10 ✓ November 1st, 2011
Fourth Boss
You beat the fourth boss.
10 ✓ January 1st, 1753
Pipe Wielder
You wielded the pipe in single-player or co-op mode.
5 ✓ May 26th, 2011
Knife Wielder
You wielded the knife in single-player or co-op mode.
5 ✓ May 26th, 2011
Perfect Win
You beat the game without continuing.
40 
Hard Win
You beat the game without using a special attack.
35 
Kill Jet
You defeated Jet and reached Stage 3 -- with Game Settings set to Hardcore.
30 
High Score
You scored 800,000 points with Game Settings set to Hardcore.
25 
First Versus
You won an online versus match.
10 
Online Co-op
You completed an online co-op game.
10 
Online Warrior
You have defeated 10 opponents on Xbox Live in versus mode.
5