[alacritythief]

A good case where this happened was with the Flash 2D "Crafting" MMO named "Glitch" created by the former Flickr founders. After the game terminated, they released all the art and source code to the public domain: https://www.glitchthegame.com/public-domain-game-art/

Because of it, two revival projects exist: Eleven (http://elevengiants.com/) and Children of Ur (http://childrenofur.com/).

I only played this game briefly when it was around and it didn't hold my interest for long, but it was a really unusual and quirky game. I'm sure the devs go into more detail somewhere why it failed, but it was likely because of bad timing-- it was a post-Farmville Flash game during the time when mobile gaming and HTML5 were really starting to kick off.

[Qworg]

Glitch pivoted into Slack. :)

[alacritythief]

It's funny that the photo-sharing part of the "Game Neverending" MMO became Flickr, and the chat tool they created to communicate while working on Glitch became Slack. It's a double coincidence of side-project success.