I had a neat idea for a feature, I don't think I have seen any hyperlinking to other saves outside the forums and saves. If you could hyperlink other saves in the comments ingame that would be fairly useful. My vote still goes to multithreading though.
jacob1:
@imkira3 (View Post)
The dates on those files are broken because they were all copied from the old server on May 20th. Can't really fix that, it just uses the file dates.
I'll make a TODO note to fix https://powdertoy.co.uk/Download/Browse.html to show all versions. The "Older" versions are so incredibly old you probably don't want them for anything. They are all from 2011 at the latest.
As for multithreading, I think we should focus on putting air in its own thread, and after that, putting graphics in its own thread. This would make tpt a lot faster, with only minor downsides. Air and graphics would both be delayed by a frame. Also, graphics functions wouldn't be allowed to modify state anymore, this should only be an issue for Lua and poorly coded mods though.
@jacob1 had some good ideas for how to do so to some extent without breaking any important functions.