41 Games: Steamworld Dig 2
To tell you why I like Steamworld Dig 2 so much, let's talk for a moment about Spelunky.
Spelunky is a game I have not beaten, but I've played enough to know it's basically perfect. With precise, but uncomplex controls, it tasks you with navigating randomly generated tombs, jungles, and [redacted] as you dig deeper trying to accumulate treasure. When you die, you start from the beginning, so every movement is a tactical gamble between setting yourself up for the future and potentially ending your run prematurely. The challenges you face (and the tools you have to overcome them) are diverse, and you get further by understanding them better.
Steamworld Dig 2 takes the act (and much of the moveset) of carving your way toward valuable treasures from Spelunky and combines it with Metroidvania-style exploration and a charming narrative. There is no perma-death here, and your upgrades are permenant, but dying does cost you, which suits this particular game well enough.
The additional elements mean it's not as pure an experience as Spelunky, but on the other hand, since its levels are hand-designed, it can sprinkle in puzzles that test your ability to use your tools, or surprise you with a wondrous sight, a tense climax, or even a nice break. And it does all of this extremely well.
I bemoaned a bit that Super Metroid demonstrated how little the Metroidvania genre has really changed since Super Metroid, but Steamworld Dig 2 (and the first one, as well, but that was far less refined) successfully puts a different new twist on the interplay of exploration, risk, and upgrades that for me are the basis of the genre.