is there any other cheats that you don't need action replay for, just plain good old cheats?
On the harbor map, if you go to the ladder on the left side of the multiplayer dock area(facing the concrete harbor from the water), you can stand at the top of the ladder and use a rocket launcher to boost yourself on top of the map. From there if you look inland and run to the far left corner of the land area on the map, you'll fall off the map into another map not found elsewhere in the game with a light house. It has a temporary door, and with all temporary doors, if you lay parallel with the door and crawl side ways you'll slide through. If you move forward when trying the door trick you're aiming too far away from the door, and if you move back you're aiming too much towards the door. Once you're through you can explore and climb a stair case on the inside. Its been years since I've played this. I miss it.