ΔV: Rings of Saturn is a hard sci-fi physics-based space mining game from Kodera Software. A unique point about the demo was that you could previously play through everything, you just couldn't save the game and now that's changing.
Read the full article here: https://www.gamingonlinux.com/2021/12/dv-rings-of-saturns-demo-appears-to-help-sales-now-lets-you-save-your-game