Maybe "mature" is applicable, though it often gets conflated with some sort of "sexual" as well.
Cawps is made by the same person as those above examples and is story-driven. It is, however, highly offensive and stupid with some sexual stuff (with explicit themes which are sometimes disturbing). According to the hacker it's supposed to be less offensive than Outlaw (which I think I gave up playing early and I don't remember the content to compare). It has humorous moments, but the effort put into "funny" dialogue is marred by the hacker's questionable way of thinking. There are also many gameplay elements that don't have much thought behind them. If you found Outlaw et al. tolerable, Cawps might be too.
A good one is Rocket Edition. It includes some more-realistic concepts with an interesting, mildly satirical story that can be seen as a bit dark. It's nowhere near as offensive as Cawps though it may have included crass humor at times (it's been a while since I played it). I played colonelsalt's version. I don't know if it's identical to the other one that got translated from Spanish (I think), which I understand is a longer game still in active development.
One of the Crystal hacks, I think by Shockslayer, has some interesting plot and gameplay elements but they were too buggy and complicated and fragmented to be really enjoyable.
Celia's Stupid Romhack is my top recommendation for story-driven but it's not really dark and is more based around a series of silly jokes and parody ideas than having a concrete plot. The current / first version which I played more recently is wholesome and lighthearted. Subjectively, I think it's the most engaging hack out there and is maybe even more fun than Rocket Edition.
