DRGS is very polished already! It's at the state where all it really needs is More Stuff. Mining materials gets you currency for both in-run upgrades and overall stat upgrades, plus you can carve out paths to escape danger or funnel enemies. Weapons have decent variety and are satisfying, and the levels give you just enough time to explore before it's time to beat the boss and escape.

Once they add some more levels and objective variety, it'll really shine, but even now it's one of the best examples of the genre.