This came out a while ago; how did you feel about the results?
I'm not the hugest fan of Death Battle since they tend to ignore information that I believe is important. With this battle, I agree that Mewtwo should have won, but they sold Shadow very short. In Shadow the Hedgehog, he survives attacks from an antimatter cannon, which has the strength of any given nuclear bomb. Since Death Battle loves obscure information, I thought they would employ that.
But no, he gets stabbed to death with a spoon.
Frankly, the only duels I agree with on both outcome and explanation are Shadow Vs. Vegeta and Batman Vs. Spider-Man.