All of those should now be fixed, except for the sand submerging stuff. I'm aware of all that, but it's system stuff that would be way more effort to fix than it's worth.
I also finally isolated a serious bug that totally broke one of the bonus bosses when you were playing a speed challenge. (Figuring out what specific circumstances THAT happened under was all kinds of fun).
Finally ... Kapow and Dimentio, I added both of you to the credits. Dimentio's been great, playing the game a lot from the start and offering lots of bug fixes and constructive criticism. And Kapow has continued playing longer than most and provided lots of bug reports for the most recent build that might otherwise have gone overlooked. Thanks a bunch, guys.
The update should be compatible with any saves made using the December 15th update file or later.