The NES mini is a joke. I'm sure you'll find ten of the 30 games included that really interest you. Then that's it. Since you can't install or insert any more games, this console won't interest you for more than a week. The NES mini is for nostalgics at best!

Dr. Mario is among the games that come with the console by default. You can hack in all NES games on it very easily. The controller cable is 1m so it is super short. You can get the 8bitdo receivers from digitec alongside with the conterollers themselves and play wireless. Here's the link to the receiver, 8bitdo NES30 Retro Receiver

I let you follow this link https://www.digitec.ch/fr/s1/producttype/controleurs-de-jeu-45?bra=345&tagIds=1-1136 I hope to have answered your question, have a nice day

Hi, I also suspect a defect. I plugged in the two controllers, started the console and it was fine.

Nintendo certainly knows that. You can find more information (rumours) via Google.

Yes, there are a few co-op titles (without splitscreen, however, which only existed on the SNES, as far as I know) where a second controller would make sense. For example, Ice Climbers, Bubble Bobble, Super C, Mario Bros. and Excite Bike. I'm not sure about other titles. But there are also other games where 2 players take turns. Unfortunately, I don't know if you need a second controller for that or if you can hand one over. I'm not good for anything today! Here is a list of the games: http://www.dailydot.com/parsec/best-games-nes-retro-console/