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.