I always loved the Needler from the Halo series. It was a really unique design at the time and probably the most fun I’ve had with any weapon in a first person shooter. Also, the explosions and the ching it does when reloading are just perfect.

Deckard’s gun in Blade Runner was always my favorite. Somewhat uncanny because it was clearly sci-fi, but retained that hard boiled detective aesthetic, like you misremembered a noir shootout.