I started a new game...
Pointer lag still exists on the main screen as well as in-game.
I fought a Formican, antelope, and the bird-like creature (forget the name) and did not experience the hang/crash, whereas with the saved game from the previous version, when I fought two different creatures, both resulted in a freeze.
Single clicking on an inventory item still does nothing, and I also noticed that hover over each inventory item does nothing unless the pointer is right on the edge of the inventory square of an item. When you put the pointer on the edge/border of the inventory square, it pops up info on that item. I am not sure if clicking on an item is supposed to do anything, it may just be that the hover pop-up came up when you were on the square long enough to click on it. Note that drag and drop still works, but single clicking on it does nothing.