Angstrom deserved it.
Mark was entirely justified in beating him to death. Angstrom’s a coward who came to torment the one version of Mark that had anything to lose, that he could torment to make himself feel better. It doesn’t matter what he experienced across the other dimensions, or what had become of his mind—he deserved to die for resolving to torture an innocent mother and her child to get at somebody he had no chance against.
What do y’all think? I’m watching the show right now, and I feel like they wanted me to feel bad for Angstrom, but I honestly don’t really care. His death scene was incredibly satisfying after everything he did.