Blizzard's team-based shooter is now in beta, and those who played on the Japanese-themed map Hanamura, could discover a location with a bunch of silly arcade cabinets.
Super Siege Mode 3 is a nice reference to the Metal Slug series and The Lost Vikings VI is something similar to the shmup mini-game from the StarCraft II: Wings of Liberty campaign. Instead of Erik, Baleog and Olaf it's about a lost Terran Viking unit.
There's also one called Fighters of the Storm 2 with 2D-fighter versions of Kerrigan and Garrosh.
Pics via LurkyTheActiveposter