I've been playing some Mario Wonder too (both co-op and single player). I'm not the biggest 2D platformer fan, but I think it does a pretty good job. I'm surprised at how difficult some of the levels have gotten so far (4 and 5 star difficulty levels ain't no joke). I'm not sure if I'll finish it, but there's fun to be had for sure.
I'm also closing in on finishing Chrono Trigger for the first time. I'm enjoying it, though I think the PS1 and PS2 era JRPGs are more up my alley. This game definitely oozes charm though, and I can see why many consider it a classic. After I beat it I'll probably try Chrono Cross again, though last time I tried playing it the game froze twice early on just talking to people...