Strategic, relaxing, pretty
Conquer alien worlds from the safety and comfort of your own, well, dome! All alone on a distant planet, hunt for an ancient relic buried in its depths, or, for more open-ended gameplay, mine resources to send back home, and maybe even return there- provided you survive. For while you're getting comfy in your tunnels, the timer ticks down until the next and even worse wave of native creatures lays into your fragile homestead up above. So keep an eye on the clock, and strategically convert resources into upgrades to match their increasing forces. The fights are about preparation and strategy rather than reflexes.
A run lasts between something like forty minutes and several hours, depending on game mode and map size. Two different domes and two keepers, each with their own upgrade trees, a choice of starting gadgets, and mineable artefacts which add unique features to your setup, make for varied runs, as do different surface environments and colour schemes. Speaking of which, both the pixel art and the music are super nice and atmospheric. Oh, and it plays fine with the keyboard, even if they recommend a gamepad.
I bought this after watching (well, dozing off to) dozens of hours of gameplay online, and I still love playing it myself now that it's on GOG. Haven't felt quite as relaxed in a game since Starbound- even as the tight gameplay loop of mining and defending keeps you on your toes and offers plenty of challenge on the higher difficulties. During my first 45-minute run, the game made 80000 connection attempts to api.backendless.com, which feels a bit excessive. Other than that a great, focused, relaxing game I can see myself return to many times.