Surprisingly difficult song

[Manuel101]

So I decided to do a Super Mario Bros bass cover playing with my thumb, index and middle finger. It was a lot harder than I expected specially on my 4 string bass. Its much easier on my 6 string bass. https://www.youtube.com/watch?v=bdCqkjtNA-8

 

[Manuel101]

The hardest part for me is at 0:26 when I am doing the bass line with my thumb and the double stops with my index and middle finger.