Mario Kart 7 launched after Mario Kart Wii and it is an even further enhancement of a game that was darn near perfect. Mario Kart 7 ditches the bikes and sticks to karts but allows more kart customizations and the ability for each kart to fly. The flying is a fun mechanic that you can strategically use to get yourself a bit further than the other karts if you can manage it and take some very fun track shortcuts. Mario Kart 7 does require you to unlock kart customizations by collecting gold coins during races.
Mario Kart 7 allows for local multiplayer by pairing over bluetooth with other nearby 3DS's. This is made dead simple in the game and I was able to easily link with a friend and go head to head locally. If your friend doesn't have Mario Kart 7 you can beam over a copy for your friend to play making it super easy to play with anyone that has a 3DS. This is a cool feature of a couple 3DS games and something Nintendo doesn't seem to be continuing with the Switch.
Like Mario Kart Wii, Mario Kart 7 has online play functionality with your friends where you can race them online or challenge your friends with track time trials. I loved the time trail challenge feature of Mario Kart Wii and it's cool to see it added to Mario Kart 7. That said, you need to magically friend someone in person on your 3DS in a way I haven't figured out so Mario Kart 7 registers that friend in game. So far how to do this is totally lost to us and even after looking online I can't see to figure it out. This is pretty frustrating because part of the fun of Mario Kart is challenging friends to track time trials and playing with them online.
Mario Kart 7 is a great addition to the Mario Kart franchise and whereas it's an old game now if you just got a 3DS or plan on picking it up there is a ton of game here to enjoy and it's not expensive. The tracks it adds are fun and inventive and the game play is buttery smooth. Each Mario Kart game in the franchise is a fairly substantial incremental improvement on the last and Mario Kart 7 builds on the amazing foundation of Mario Kart Wii. I wonder if Mario Kart will take a page from Super Mario Maker and enable some kind of user track creation toolkit in some future release? If Nintendo did that I think that would be the greatest thing to happen to the series but until then Mario Kart 7 is a good addition to an already great series.