My favorite emulator, RetroArch, is now available on iOS, so I can play my favorite retro console games on my iPhone or iPad. The current release is not optimized for the iPad, but like all/most iOS, it will run on the iPad in an upscaled mode. While this could be better, it’s good enough for now. 

Setting up RetroArch to handle a wide range of consoles is overwhelming. Thankfully, some good guides like this RetroArch Starter Guide. If you prefer a video walkthrough, I prefer this RetroArch on iPhone & iPad (Starter Guide). Both are great resources by Russ at Retro Game Corps, which is one of my favorite resources for emulation software and hardware. 

If you are looking for a great controller, I own way too many 8BitDo controllers. They are my favorite gamepads and arcade sticks and a family favorite in my household for our Nintendo Switch, too.