Head to the in-game cheats menu and insert the following numerical codes on the left.

28260 - Unlocks One Hit Dishonor

65049 - Unlimited Health

66206 - Unlimited Specials

85061 - Unlocks Gallery

89121 - Maxes Out Your Level

90210 - Unlocks 2x Damage

99801 - Unlocks All Bonus Games

You can achieve the entire 1000 gamer points in the FIRST 5 minutes of this game, Every 10 hits you get without getting hit yourself gets you an achievement, 5 achievements total, 50 hits to get them all. At the start of the "Book Two" Level (first level of the game) run all the way to the left of the screen and start pressing the B button to fire at your enemies. Remember Dont Get Hit! That Easy!