I like to imagine that Shadow is actually very sensitive deep down and that all the various storylines depicted in Shadow the Hedgehog happen entirely in his head as a way of venting his numerous frustrations. This would help to explain how overpowered Shadow is compared to his Sonic Adventure 2 incarnation, and how a number of the storylines forget about the central plot conflict partway through to devolve into meaningless revenge tangents or abject silliness (usually both).