To get 4 free lives each time your game is over, walk past the continue door to the left and there is a room where you can collect them.
In the hall of rooms, walk left until there is a door above you. Push up to enter a secret room; collect all the stuff in this room. Then walk directly up that door and puch up, here you'll find more treasures and goodies.
First Power-up---"&1#1#" | "L1191" - Extra Energy
Second Power-up--"?1S1M" | "61H1C" - Rescue Pugsley
Third Power-up---"BLSRS" | "B&198" - Rescue Granny
Pugsley----------"V121B" | "B?KKV" - Rescue Fester
Wednesday--------"VD2RL" | "BLS1T" - Rescue Wednesday
Granny-----------"V&YKW" | "#Z6D?" - Game Ending
Fester-----------"VL#R4"
"&1Y1M" - 3 hearts (after the big tree)
"?191D" - Hearts (after fridge in kitchen)
"B919D" - 5 hearts (after conservatory)
"V1S14" - Pugsley (Games room)
"V919B" - Fester (Picture Gallery)
"BG9K&" - Wednesday (Crypt)
"BLJK#" - Granny (Kitchen)