Nope, Mario has at least two running speeds, sometimes three depending on the game, and the only game that’s “Flat” is the very first one. And it’s only even partly true here, there is plenty beyond flat ground to do even here. And lots of hills and different terrains and heights in the sequels. Have you even played any besides the first one? And his jump also changes depending on your momentum, you can jump both higher and farther depending on how fast you’re running and how long you’ve been running and that’s even true for the first and second games, which I might add are the only two where he only has two running speeds as opposed to three.

I just stated my opinion that I think Mario feels better. If you like sonic better there is certainly nothing wrong with that they are well designed games for sure, but you don’t have to make up facts that are in no way true to do so.