On the title screen type "THE PERFECT KISS" for infinite special weapon while your the wolfman.
On the option screen type "SOULPSYCHEDELICIDE" for a full active life meter.
During play type "ITS NOT ALL WALKING" and when your game ends a new option will be waiting for you on the options screen. This new option will let you start at the last level you were on. No good if you didn't get past the 1st level.
NOTE: You may only have one of the above activated at a time. I suggest you use one of the 1st two and when your on you last life and close to death type the 3rd one. Now go to the option sceen and type the second one. This will allow you to continue at the last level completed and give you a full active life meter. Repeat if needed.