Back when I could get really into ridiculously simplistic Flash games, I found a game called Motherload, in which you mine Mars for valueable minerals. It was great fun until my second session when I discovered that the game only saves your items and money, but not the actual world, so every session, I had to dig a new mine, which is surprisingly expensive, even with high-level upgrades, but nowhere near as expensive as it is tedious. I'd better move on before I end up reviewing a crappy Flash game from years ago that nobody cares about anymore.
SteamWorld Dig reminds me of Motherload, and simple, arcadey Flash games in general. It's what I imagine some of the Flash games I've come across over the years would be like if they were developed further, and for a platform that's not a bloated mess.
You play as steam-powered robot Rusty, in a world of steam-powered robots, as he arrives at a tiny mining town in the wild west. In the opening cut-scene, the ground opens up, conveniently dropping you into the mine for a tutorial level. A slightly morbid tutorial level in which you find your uncle's corpse and pry his pick-axe from his cold, dead hands.
The plot revolves around exploring your late uncle's mine under the town, with gameplay similar to that of Terraria, but with larger blocks, a much narrower world, no crafting, and a set plot with linear progression. I'm not making this sound much fun, am I? It is fun, really, but it's very mindless. The only challenge is in mining without leaving any ore high up in a wall or digging yourself into a big hole and having to spend all your money on ladders. Other than that, the game is so straightforward that it would bore me if it weren't so hypnotic.
If you like games that are simple and easy to get into a rhythm when playing, this is a game for you. Although you may get completely screwed if you die a lot. Death, or more precisely reassembly after death, costs money, and there is only a finite amount of ore in the game to sell, so if you reach a point in the game that's giving you a lot of trouble, i.e. killing you a lot, then you may find yourself strapped for cash when you next need to upgrade your equipment to progress further, because you have to upgrade your axe and drill eventually as the ground gets harder and your puny equipment can no longer break through the blocks, no matter how many times you hit it. I could be wrong about deadlock being possible, but since I got to the end of the game without enough money to buy all the upgrades, I strongly suspect that it's possible to get completely stuck and have to start over, so that's the games' first major failing.
The second major failing is the total dick move it pulls at the end. There is hardly any combat in the game; you can mostly just avoid enemies, and if you do need to pick off some buggers that are standing between you and some loot, the earliest ones can be killed with a few whacks of the pick-axe, and later on you get a ranged weapon with effectively-unlimited (and free) ammo to take care of the tougher enemies. So what's the obvious climax for a simple mining game? A boss fight, obviously.
The game was really charming until about two thirds in, when it started to just get tedious, and the story started getting really cliche. A game that gets worse partway through gets no more of a recommendation than a game that starts out bad and gets better partway through, but for what it's worth, SteamWorld Dig is quite fun to start with.