The updated version I was talking about earlier (version 1.0.3.) is available to download right now. I wasn't able to test it on lower-end machines, so I'm not sure how much it actually improves performance, but I did some optimizations. Feel free to try it, but don't feel obligated to :)
Yes, Plead with the Elder Gods is basically a sequel. It will have many of the same gameplay elements (platforming, exploration, metroidvania-like upgrades and progression) as well as similar thematic elements. The full game is still a long way off, but we're working on a demo right now. I think people who like/are interested in Mountain God will also enjoy Elder Gods.
-Jay