As old as this thread is, I'm surprised I haven't posted my best game I have ever played sooner...
The best game I have ever played (or my all-time favorite game) goes to two games in particular. Rayman Origins and Rayman Legends. Ever since I played both games back to back in the Summer and Fall of 2013, these games are and probably will be the best 2D platformers I will ever play in my lifetime. Both games have outstanding visuals, really nice soundtracks, and each level in Origins and Legends always has something new to bring to the table and the difficulty curve is nice and smooth. These two games are probably where most of my inspiration comes from with drawing and art in general, and a huge inspiration for level creation when it comes to SRB2.
I can write a whole 5-page essay on why Origins and Legends are the best games I ever played but that's for another day. For now, if you are really looking for a fun 2D platformer to play with your friends and family locally, I highly recommend trying out Origins and/or Legends. Especially Legends since the Definitive Edition is coming out to the Switch soon.