Currently Online 
So just to go over my experience.
I give Super Mario Bros Wonder a 97 out of 100.
Took me 12 hours
When comparing it to the rest of the series I played...
Super Mario Bros. (NES): 80
Super Mario Bros. 2 (NES): 73
Super Mario Bros. 3 (NES): 92
Super Mario World (SNES): 93
Super Mario World (NSO): 94
Super Mario 64 (N64): 90
Super Mario 64 (NS): 90
Super Mario 64 DS (DS): 86
Super Mario Galaxy (Wii): 89
Super Mario Galaxy 2 (Wii): 95
Super Mario 3D Land (3DS): 90
Super Mario 3D World (WiiU): 94
Super Mario Odyssey (NS): 98
Super Mario Bros Wonder (NS): 97
Super Mario Land (GB): 63
Super Mario Land 2 Six Golden Coins (GB): 80
Super Mario Bros Deluxe (GBC): 82
Super Mario All Stars (SNES): 100
New Super Mario Bros. (DS): 80
New Super Mario Bros. Wii (Wii): 90
New Super Mario Bros 2 (3DS): 84
Super Mario Advance (GBA): 76
Super Mario Advance 2 Super Mario World (GBA): 93
Super Mario Advance 3 Yoshi's Island (GBA): 97
Super Mario Advance 4 Super Mario Bros. 3 (GBA): 92
+Great level design, great gameplay, visuals, music, sound, overall production is great
-Some levels could be unforgiving and depending on NSO/Online is needed unless you dont mind re-trying a million times.
I'd hate to see the game with no online, I mean it can be doable but the last few wonder seeds you'll need for the main story will come down to the harder levels.
Also I love the push for a story/character interaction in the beginning of each world and at the end of each world. Its not much but I still appreciate that they at least try to add more character development/interaction and hopefully more Mario games will have that in the future specifically for the 2D ones I mean.
Edit: Actually now that I think of it...this has been the shortest amount of time it took me to beat a game that I bought not only year 1 but in just general since...Paper Mario for N64 back in 2000 (which I beat the game in three days with about 21 hours).
9 days after release - not bad.
