Easy leveling
Enter Fortune Park, and go towards the Atlantica Casino, but do not go in. Instead, follow the wall right until you see a maintenance door. There should be a stick of dynamite and a hunk of meat right outside the door. Pick both of these up, then enter the maintenance room, and combine them to get the Dynameat. Next, go to the fireworks stand, grab some firecrackers, and jump up on top of the stand. Lure a large amount of zombies near you using the firecrackers. Once there is a large group of zombies, jump into the middle of the crowd, use the Dynameat,
and then get out quickly. Once it explodes, you will get a lot of PP. Once you enter a nearby place, all the items will respawn. Repeat this as many times as desired. Note: This trick is still very effective at levels 45 and higher.
Easy money
Collect all three gambling magazines. Then, go to Slot Ranch Casino, and play the large heart-shaped single pink slot machine on the first floor near the access point to the Food Court. Keep betting the max of $1,000 to win a lot of money quickly. It is possible to win approximately $1,000,000 every ten minutes. Note: Sometimes you may not win anything for three minutes, but then you may win three times in a row. Just keep playing until you win the desired amount of money.
Bonus costumes
Successfully complete the indicated task to unlock the corresponding costume in the safehouse closet:
Champion's Jacket: Win a TIR episode.
Convicts: Kill ten psychopaths.
Dealer Outfit: Change into all available pieces of clothing, except locker items.
Hockey Mask: Use all melee weapons on zombies.
Tattered Clothes (Shaun Of The Dead outfit): Kill 1,000 zombies using hand-to-hand combat.
TIR Helmet: Earn $1,000,000 in TIR Online.
TIR Outfit: Earn $5,000,000 in TIR Online.
Willemette Mall: Rescue 50 survivors.
Ghosts 'n Goblins knight armor
Collect all four pieces of the knight armor to reduce damage taken to half. However, if you lose 50% health, the armor will break and you will take normal damage in your underwear. The armor pieces can be collected as follows:
Beard: In the rear of the "Wave Of Style" hairdresser's shop in Royal Flush Plaza.
Knight's Armor: Successfully complete the game with an "S" rank.
Knight's Boots: Purchase for $2 million from "Moe's Migitations" on the Platinum Strip.
Knight's Helmet: Rescue Jack in the "Meet The Family" mission, and defeat him in a game of poker in the "Ante Up" case.
Alternate endings
Successfully complete the indicated task to unlock the corresponding ending sequence:
Ending A: Successfully complete all cases, give Katey the Zombrex each time, and do not give TK the Zombrex before completing "The Facts".
Ending B: Give Katey the Zombrex each time, but starting at Case 6-2, allow the time to advance until 7 a.m. on September 29, and do not complete "The Facts".
Ending C: Give Katey the Zombrex each time, but do not complete Case 6-1 or fail any other case before Case 6-1, and be in the safehouse before the military arrives.
Ending D: Be outside the safehouse when the military arrives.
Ending F: Do not give Katey the Zombrex, and be in the safehouse when the military arrives.
Ending S: Successfully complete all cases, give Katey the Zombrex each time, and give TK the Zombrex before completing "The Facts".