Tropers / Gunpsycho

While I can't really remember how I found this place, I've taken quite an interest to it thanks to videogame tropes such as That One Boss.

My first contributions to the beat-em-up page of that trope is R. Bear from Streets of Rage and Slice and Slisaurs from the Cadillacs and Dinosaurs arcade game, but I will be on the lookout for more obscure examples of such, even those of other genres.