Cave story
About the game
Cave story is a freeware indie game developed by Daisuke Amaya in 2004. It is a platformer game that takes place on a floating island.
You wake up as a robot with no memory and you start poking around a cave. Soon enough, you find the Village of the Mimiga and quickly encounter some allies as well as some enemies. With the Mimiga called Toroko getting abducted, you quickly have to start exploring the rest of the cave to rescue her as well as figure out why she got taken in the first place!
I won't go into the whole story here, it's best to play it yourself and it is not a particularly recent or hard game to find on it's own. The thing has been ported a lot (though not nearly as often as DOOM).
I have a lot of fond memories beating this game a few times as a kid, it's got a great soundtrack, and it's a game I think about often.
For a little freeware game devleoped in free time over the course of five years it's a pretty good gem of a game.
Where to get the game
There are a lot of places to get Cave story
There's the Free translation website, Steam, As well as the Epic Games store.
I personally would reccomend either getting the translation or getting the epic games store version, just because there's been some bad dealings with Nicalis as a Publisher and Studio Pixel not getting a whole lot of the cut through that avenue, while if you do want to support Studio Pixel you should consider buying it through the Epic Games store area or buying some of Pixel's Other games if you do decide to not simply get the translated freeware version of the game.