It depends on the Twine game, but I didn't do any special mobile formatting to make the game look good on iOS. I don't see why it shouldn't work, though. Although...the games include images now, and I'm not sure you can load those on iOS?
I just started the game up on an iPad to see what it takes. TWINE (and HTML games in general) are the only easy way to get adult games on iOS.
Very simply, the game is fine, but the delivery system is not. The only thing which might not work is if the game included webm (I don’t know if TWINE can do that), and even then it would just be those movies which don’t work.
If a game is hosted online, there should be no problem. “
You must be registered to see the links
” by Westane is an example of a TWINE game hosted online, and it’s totally fine on the iOS version of Safari.
Most iOS browsers can’t download files, and most downloaders can’t unzip files. To download you will need a separate app, like Mega or Dropbox. The Mega app will let you “preview” a zipped file, but not unzip it, so you can play most HTML games without images. Basically, you can view one file in the zip, but there is no file structure created so that file can’t link to any images or anything. The game will run, there just won’t be images.
To unpack a zip, rar, etc. and actually create folders you’ll need another App. I use “Documents” by Readdle. It’s basically a file manager, but it can uncompress things, and it has a web browser. When I unzipped this game in Documents, it works fine. The only problem I’ve run into with Documents is that when a game has a lot of patches (like say, “A Spell for All”) it cant merge folders, so a patch folder with 4 images will overwrite the old folder which had 96 images. The user needs to copy everything to the exact folder where it belongs. (The way “A Spell For All” is organized is particularly easy to break the game if you apply the updates wrong.)
The best thing developers can do to make their games work on iOS is to host them online in some form. That gets around the difficulty of importing porn into Apple’s walled garden.
Since putting the game online is not always a possibility (and these sorts of games are usually a labor of love) Mega and Dropbox are probably the best options for downloads, since they have apps on the App Store and aren’t phishing schemes like most other hosting sites (“Dear Amazon User, you’ve been selected for a free iPad!”). Other than that, the only other thing a developer can do is to always release the complete game as updates instead of expecting the user to patch it.
EDIT — I wanted to add that Patreon complicates things a step further. Attatchements there give JavaScript errors in most iOS browsers, so to download from them I use Aloha browser, then if the file needs to be unzipped I copy it over to Documents. Basically none of this is the fault of a developer and it’s all very opaque because if any of the third parties advertised their apps as being easier ways to put porn on your iPad, they couldn’t be on Apple’s App Store.