Seven Samurai 20XX Cheats

Finish the game one time and save it when asked. 
Pick load game and it will start a new game with your stats.  Use
the katakana in both hands by pressing L1 + R1

To unlock Survival mode complete the game on Normal difficulty.

Complete the game and at the end, when prompted, save your game. Then, from the title screen, load your saved data to start a new game with everything you had when you beat the game.

Defeat all the Bosses in one game session on any difficulty setting to unlock Coliseum mode. You must fight all thirty Bosses consecutively in Coliseum mode.