The Mega Man 4: Free of Charge download comes as an IPS patch file. There are free utilities out there like Floating IPS that can apply the patch file to a clean dump of a NES cartridge.

Mega Man 11 made its debut on the Switch and multiple other platforms in 2018 and here on Nintendo Life at the time we gave it a solid 9 out of 10 stars: "Mega Man 11 is a modern classic ...