All right, here you go. Probably the best I can be bothered doing.
Dead Horde +5
Options:
Infinite Ammo / Grenades (or second weapon)
$500,000 cash when you buy something
Infinite Stamina (mash that spacebar and the dude will run then roll when you stop)
Infinite Health (does what it says on the box)
One Hit Kill (fat zombies only)
Each zombie type has its own unique routine for health. So that's a pain. The fat zombies are the hardest ones with around 800 health each. This gives them 1 health and a single shot from anything will kill them.
Upgrade the Shotgun for 1-2 hit kills on most enemies. You can't die, so even if they take 3 shots, it won't take more than a second or two to kill them.
And if you feel like doing something nice for someone, find an elderly neighbour that could use your help and do something for them. At the moment there are lots of people who would appreciate a small nice gesture.