After completing the game, instead of starting a new game, use the level select cheat and start on the first level. You will keep all your weapons and upgrades from the last game.
Complete the game under any difficulty setting. Start a new game, press ESC to display the "Options" menu, then select "Cheats". The following cheat options may now be activated.
1. Low Gravity Ragdoll: Enemies will fly away when killed. Put them on orbit by destroying their oxygen tank. 2. Extreme Ragdoll 3. Hippy Blood: Changes spilled blood into colorful flowers.
