Zero Sum Game is a parser-based comedy game by Cody Sandifer, published in 1997. In it, you play as a newly victorious adventurer who, upon returning home, gets scolded by their mom and who then has to go and once again set wrong what has been made right. It's essentially an adventure game where you have to lose all your points and undo all your heroic conquests in order to return back to your mom's good graces.
The writing style alternates between imitating a lofty high fantasy style and being jeering and sarcastic, and there's a very cynical undercurrent running through the whole game. This is a world where so-called heroes are not necessarily very heroic and all life is expendable. The humor is dark and uneasy, downright sociopathic at times. But - if you don't mind twisted humor, adult themes and doing villainous things in an adventure game, you'll probably find the contrast between the fantastic and crude here at the very least amusing, if not hilarious.
It helps that the implementation is extremely detailed, with certain sections almost sandbox-like in their wealth of interactions. The game is packed full of funny responses to actions; there are even a few animated NPC characters who react to your odd behavior, and sometimes to each other as well.
The game is very difficult, though. There are countless of ways you can make the game unwinnable, and although the game provides a "warning" command to let the player know ahead of time when they've done something irreversibly dumb, the system doesn't seem quite fool-proof, as I found out on my first playthrough. It took three restarts total (with the use of some hints) for me to finally reach the ending.
The puzzles themselves are sometimes devious and clever, possible for a player to figure out if they play around with the mechanics enough, but there are some nearly impossible ones too. One part requiring the use of a non-standard verb while being misdirected by the game and also (Spoiler - click to show)the merciless timed section featuring Benny/Darlene come to mind.
Zero Sum Game is something of a mixed bag, personally. It made me laugh a lot, but it didn't make me feel good in the end. I guess such is the nature of dark comedy. And while the game has a good amount of content - you can easily squeeze around two hours of gameplay out of it - the daunting difficulty with the lack of an internal hint system is another thing that makes the game hard to recommend without reservations. You should probably give it a try if you're into deconstructive and satirical humor, at least.
Ecdysis is a parser-based Lovecraftian horror game by Peter Nepstad, published in 2007. You're a man who wakes up at night to a pounding headache and weird visions. You get up and eat some pain medication, descend down the steps, feel strangely sweaty... and from there things only get more and more strange.
The game is very short - under 10 minutes long - so there isn't much else that can be said about it without spoilers. But in general, I think that the writing is descriptive and memorable, and the game definitely has a certain "shock" factor to it that makes it worth trying despite its brevity.
While the game world is rather linear and small, the implementation can get bizarrely detailed at times. The author gave the main character individual body parts like hands, feet, head, eyes and yes, even sweat, that have their own descriptions (Spoiler - click to show)that change as the adventure progresses because of... you know. There are also some non-standard verbs like "think" and an optional side quest where you put a blanket on one of the children. So, if you're the sort of player who likes searching for secrets and details in the game world, Ecdysis has some interesting things to find.
It should be noted that the game has a lot of glitches too, although to be fair, they don't hinder a regular playthrough at all. I guess you could think of them as just another "bonus feature" for the observant player. For instance, (Spoiler - click to show)you can make your own body parts fall off using the buggy "cover" verb. Try the command "cover me with eyes", for instance. A glitch like this suits the body horror aesthetic of the game surprisingly well, though.
Ecdysis is short and sweet. Well, maybe it's more sour and horrific than sweet, and its short length keeps it from being absolutely essential playing in my opinion, but it's an interesting title to try out if you have a bit of time and like parser-based horror.