A dating sim where you smooch skeletons and zombies
Otome ("maiden") games -- typically localized from Japanese or Korean -- are all the rage these days, and the settings are many and varied: Destiny Ninja is about dating ninja, War of Prayers places you in the role of a magical girl who falls in love with her bodyguard, Hatoful Boyfriend replaces the conventionally human love interests with birds... You get the idea.
One of the biggest publishers of otome games for smartphones is NTT Solmare, best known for its Shall We Date? series. In 2014, NTT Solmare released The Niflheim, and even among a genre which includes dating birds and anthropomorphized pieces of sushi, this is an oddball: your heroine wakes up dead in a Burtonesque underworld and romances one of several varieties of undead creatures. There's J.J., the zombie; Nick, the ghost; Victor, the Frankenstein monster; and Skeletiano, who is (wait for it) a talking skeleton.
(There are a few others who are a bit more conventional-looking, but none of them are the gorgeous and whip-smart Sunny, so who cares.)
The Niflheim never downplays the fact your would-be paramours are all dead. Chunks of J.J.'s rotting flesh periodically fall off. Skeletiano's route involves loving descriptions of kissing his handsome skull. You get hilarious little worldbuilding descriptions about blood-flavored macarons and the heroine likening sexual excitement to getting cremated. If you could imagine Tim Burton's Corpse Bride but with a more satisfying ending, it would basically be this game.
As smartphone-based dating sims go, The Niflheim is also one of the better localizations out there. Typos and stilted language do crop up from time to time, but mainly in the optional side stories rather than the core character routes. On the other hand, some of the chapters are gated and require either in-app purchases or a boatload of in-game currency to proceed. Though the in-game coins can be accrued at a decent rate if you're patient enough, it would be nice if NTT Solmare just let you buy an entire route for a flat rate, as it does for some of its other games. Especially now that it's stopped releasing new content, as far as I can tell.
Still, if you're looking for a fun, quirky, and kinda gross dating sim in the spirit of October and Halloween, I can think of few as charming as Shall We Date: The Niflheim. You can download it from Apple's App Store or, if you're on Android, the Google Play store.