This save (Normal difficulty) starts off in the beginning of the game on the rooftop just after batman gets his suit.
This save gives you an instant level up to lv 90,000 or something like that, enough to get all upgrades.
Please let me know if you have any issues.
Please note that once the save starts, the game will TEMPORARILY FREEZE, but if you wait like less than a minute (or more im not sure lol) it should start and you will have max upgrade points
all credits to Jappi.