this was originally gonna get posted to https://e621.net/forum_topics/58612 but it's kinda derailing... check out that thread if you need some urls to search thru
i found a way to download all the assets from browser games (no guarantee they'll be playable, the worst you'll get is an asset dump, which is still pretty good)
my method works on firefox.
1. open inspect element on the game frame or nearby 2. search around for an element with id= "game_drop", copy the url the "src" of that, it should begin with https://html-classic.itch.zone/html/ or something like that 3. go to that url, now open inspect element again, go to network tab 4. hit the garbage can at the top left to reset your cache 5. hit Ctrl+R for hard reload 6. wait until all the assets are recieved, it should all appear in the network tab... typically done at startup, but a few games do this annoying thing where it only fetches assets just before they're rendered ingame 7. hit the settings icon at the top right, click "Save All as HAR". check the file. if it's 0 bytes you didnt clear the cache properly or something else fucked up
there's some software out there that lets you see the content of HAR files, ill leave you to figure that out, but the important part is the downloading.
anyway, if you got nothing to do today, find games through this thread or wayback machine listings of NSFW itch.io browser games (most of them are still available just unlisted AS OF NOW) and start downloading stuff you like, cause it could get lost very soon.