I always thought of the NSMB games kind of like spiritual successors to Mario 3.
Which confuses me as it had a sequel (a far superior one, mind you), but New Super Mario Bros. and New Super Mario Bros. Wii both had similar world designs, similar concepts (enemies on the map) and generally, you could see what Nintendo was going for.
But this is just a level swap. :U
Now, Sonic Fan Remix is DEFINITELY a remake of Sonic 2. Graphically, it's different, in terms of gameplay, it's the same old Sonic 2 I play on a regular basis. n_n