RimWorld drops Unity for its own in-house engine, says your saves still work, so do most mods, and the whole thing runs twice as fast

"We’re announcing update 1.7, which moves RimWorld from Unity to the Waylith Engine, our own in-house engine built by Ludeon Studios. The game looks and plays exactly the same, but in our tests performance is improved by 2-4x. "You can try 1.7 right now on the unstable beta branch… We stress-tested a late game colony and saw 2.2x better performance on 1.7 compared to 1.6. A modpack with 1,500 mods (!) went from 14 minutes to 6 minutes to load.