Here's a demo to an RPG that I've been working on for the last year or so:
The final game will eventually be a downloadable exe, but I wanted the demo to be playable online to maximise the number of people who would be willing to play it. Here were some unique challenges I had with making an online demo version:
1. Streamed music files wouldn't play consistently, so I had to make all of the game's music pre-loaded sounds. Not ideal, but it worked.
2. Itch.io has a 500 file limit for online games, although apparently this can be increased if you ask nicely. My demo was pushing this limit, which meant I had to get rid of a lot of superfluous assets. Anyone hoping to make an enormous online game for itch.io should be wary of this limit.
3. Some players turn off hardware acceleration in Chrome for screencapturing purposes, but this effectively disables WebGL. So I had to put in an "if effects enabled" check to give those people an error message that instructed them to try another browser, turn on WebGL, or download an exe version.
4. My dialog system works with text files loaded with AJAX, but I switched to just using giant global strings to remove the possibility of the dialog breaking for someone with a bad Internet connection.