An invulnerability cheat is a good idea, but please don't make it a Patreon exclusive, because it wouldn't work with the game when you would keep on dying over and over.
and will it be a god of war type of game? because god of war has an easy difficulty. All the god of war games do. god of War 1 is as hard as dark souls in the easy difficulty when you were progressing (they should have thought that through when they are making the game) but at least the other god of War games are better to beat through at least.
edit: make sure you get hit by half of a heart, not a full heart, because as you say the players messaging you, they can't upgrade the character fully and it makes the game into a dark souls rip off. and it wouldn't work in the game
and I have 2 requests.
request #1: will you make the weapons upgradable, including the main weapon to add more damage?
request #2: will you make your character bigger and bigger for the sake of inflation and weight gain?