For co-op, need to save/load:
Keys/Objective items
Heads
Tokens
Levels Unlocked (this is currently handled by OR'ing level unlocked bits among all characters)
Ammo/Capacity
Need to start with all characters - 801E6040 00FF
	(OR 0x07 unlocks base Lupus, Juno and Vela which resolves character issues)
Need to make a "press key(s) to respawn" code (L is a good choice)

Data can be loaded by copying a file and pressing L to copy data from 0x801E6010 to a spare address, then copying this data back to its original location when in co op (use 0x800A5060 - Mode byte to differentiate between the copying modes)

Data can be saved by constantly copying co op data to 0x801E6010 (after OR'ing unlocked levels to the multiplayer data from the 0x801E6010 area?) and then saving normally

NOTE: In the trainer version of this hack, the latter method is used for saving, but loading is done from the save memory normally (or from the ROM if the now deprecated online hack is used).
