The Binary BlobIt's super-old, but I've been playing the #RiftBreaker. It's a bit of RTS, a bit of tower defence, and a bit of a dungeon crawler. You jump to a (procedurally generated?) map in a random location and then you either explore or build a base to exploit the local resources. The difficulty on normal feels like it's not enough, I'm not done but the final creep wave that comes when you open the rift portal back to Earth is supposed to be huge.
The most interesting thing I've noticed is that difficulty scales with the number of side-objectives completed. Unique creeps from the different biomes start showing up in waves attacking HQ. For example, there's a snail thing that lobs bombs at you from a long range, which forces you to either jump into the fray to clear them out or to build super-long-range artillery towers.
It was also the very first thing I reported on protondb, works pretty great on linux! (well after a config change to force directx11 to stop it from crashing randomlly after teleporting :( )