I regularly use mine as a couch co-op party system, though usually we are playing Steam games, not emulated games. I have played emulated WiiU, Wii, PS2, GameCube games, however, and have found that multi-controller support can be a pain with the emulators needed to play.
Hardware wise, it’s rock solid for Bluetooth controllers up to four, but no more. If you need more than four controllers, you will want to wire them in with a USB hub. We’ve played plenty of six-person Teenage Mutant Ninja Turtles brawler using four Xbox controllers, one person with a wired steam controller, and one person holding the steam deck as the last controller.
If you go for older retro games, N64 or earlier, it gets a lot easier as retroarch is easy to play around with in game mode, where if you need to get into dolphin or something you have to go into desktop mode to make tweaks and it’s just a pain, imo. This is why we typically play older stuff or steam stuff. Steam stuff is easy because it just works.
It’s also super portable and I can bring the whole setup in a backpack and just requires a USB C laptop charger, my usb c dock and a HDMI cord.
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