Other than not having the right kind of voice/vocal range to pull off Fallon's distinctive gruffness and the mediocre guitar playing it wasn't bad. I've give you a tip if you were playing live music at a bar I was at.
I can't play guitar for shit, I know I don't sound like Fallon, but I don't try to, there'd be no point in covering a song if you were just going to impoersonate the original artist.