The easiest thing to fix was the oddest to encounter at the playtest. At the start of the 3rd level, after the player used the Gravisphere for the first time, it got stuck between states and couldn't fire anymore, but it unstuck on reloading at the next checkpoint. Luckily the next checkpoint could be reached without using the tool, or the playtest would've ended at that point. The solution was obvious after a single test in the editor - the crate in the first room, which I had just added a day or two prior, had no parent, which caused an error. This makes sense, since it hadn't occurred in any of my tests leading up to the playtest. So many people had the problem, I thought it had to do with some broad error, but it was specific to that crate. That means many, if not all, people tried to lift that crate, which was the reason I put it there, so that's good.
For many months we've needed a better way to show where held objects will land when dropped, to make for easier precise placement, especially at long ranges. This has been drastically improved by growing the particles around held objects, as pictures below.