Downwell occupies a similar space in my Steam library as Nidhogg. Tense, kinetic, focused, ridiculous. But instead of swordplay, we're rescuing our cat from the bottom of a miles-deep well while felling innumerable eldritch horrors by bouncing atop their heads.
Oh, and you have gun-boots.
It took me a shameful amount of time to beat Downwell, but the fact that it gripped me for so many hours is a testament to a few things. First, how easy it is to just dive into a game. Most attempts don't last longer than a few minutes, and a successful run takes perhaps 15-20 minutes, though of course it'll take you a great many tries to get that far. Second, how wonderfully agreeable Downwell's controls and mechanics are. The game is punishing; your faults are your own; and every shot, every jump, every single tiny moment is just so gosh-darn exciting. It never lets up.
Also those gun-boots are really clever. Every time you shoot a bullet out of your boots, you propel yourself upward a little, slowing your descent slightly. And since you descend at a blinding pace most of the time, you often need to shoot just to slow things down and take stock of your new surroundings and enemies. But you only have a limited number of shots before you have to land somewhere - either on the terrain or bouncing on the head of a hapless blob or bat - to restock your ammo.
So in a rather convoluted way, Downwell has a bit of resource management going on under the surface. The resource is your ammo, and every second or so you'll have to decide whether to use it to kill enemies, or slow down and take control. Because if you want to do both, Downwell's got some news for ya, bucko.
The loveliest moment arrives at the end, after you've defied all odds and bested the beasties that occupied this well. At long last you reach the bottom, where you reunite with your dear feline companion, who seems perfectly fine (if a little hungry for attention) after its horrifying ordeal.
I've beaten many difficult games in the past, but only one of them has ever given me an adorable pixel cat at the end of it all. Now that's a reward that's worth the trouble.