Mammal is a small-to-medium-sized treasure-hunt game with mild puzzles. As the human slave of reptilians, you are tasked with eradicating all traces of mammals from a museum.
(Spoiler - click to show)This is a fairly grim premise, since you're effectively a Sonderkommando. The wider context of the purge is never explicitly stated, but there's ample evidence that it has been a violent and chaotic process. The featureless protagonist shows no signs of emotional reaction, and dutifully goes about a set of simple tasks that are perfectly familiar to an IF player: find and identify the treasures, solve some mild puzzles to secure them, return them to the trophy-case. The PC is wholly subsumed by their role.
There are some obvious homages: the skip as trophy case is a throwback to Ad Verbum, and the reptilians bear no small resemblance to Dr. Sliss of Rogue of the Multiverse. (If there are any direct references to the TMBG song, I wouldn't notice them.) More generic stock IF devices are common, too: a crowbar to pry things with, a wandering cat. This is about the morally numbing effect of familiarity, of how having an excellent practical grasp of how to do something can make it seem less ethically troubling. That this is a mechanically unremarkable game is kind of the point. The puzzles are just fiddly enough to engage your attention and keep it away from the elephant in the room. Ultimately, you incinerate yourself for the lousy last point. (I assume; there's a point or two that I haven't found.)
Mammal is not an ethically deep work; it has a single trick to pull, a single point to make. But it's cleverly handled, and it delivers a mean little moment of realisation. And it's very clearly not about the rather tired point that players will cheerfully do atrocious things if shepherded by gameplay; rather, it takes that as read and takes advantage of it.
(There is one small bug: if you incinerate yourself while holding other mammals, the other mammals are not incinerated.)