There are two games in development. The first, DRG survivor, is made by an entirely different team and is actually a proper spin-off.
Rogue Core however is made by the original team and originally started life as a DLC for DRG, but they quickly realized it wouldn’t really work with the existing gameplay loop and decided to make it a standalone game instead as that would give them more freedom with it.

It definitely has a strong ‘cult following.’ Check out it’s SteamDB page.

Discovered it 1 month ago with this video, having a blast with the game