When you type "314142" at your main menu you will have the option to freeze your enemies.
One Hit Kill
When you type "162226" at your main menu you will have the option to use One Hit Kill.
To enable Invincibility go to your "Cheat Menu" and enter 132136 as code when you have open the "Enter Code" option.
Unlock Game Mode+
For this you need to complete the game once..