Hmm... there seems to be something up with LOS behavior in this build, but I don't see any changes to LOS in the changelog. It might have to do with Sprite changes.
What's happening is if the Y position of a Sprite is exactly equal to the Y position of the object with LOS behavior, then the Sprite is completely invisible as long as it's on the left-hand side. I'll try to mock up a demo showing this.
Here it is:
Run this in 0.99.3 to see what it's supposed to do, then run it in 0.99.4 to see the difference. A hotfix on this would be super-swell (that is, if it's easy to do and stuff...)
Platform School seems to be running okay, aside from a bit of a gravity issue when swimming. But I assume that has to do with the new gravity settings, and it seems I can fix that pretty easily. So barring any unforeseen difficulties it looks like work will continue on Platform School here shortly