Heck yeah R8BDM is REAL! You can download it if you like...!
There is a V4 Teaser that could possibly reveal more Robot Masters, more levels, & more features (just hypothesizing)...!
It does have Multiplayer, but it can work better with Doomseeker. As long as you follow a good walkthrough to set it up. It tried it & it fitted me just nicely...!