I thought I'd be good at this since I do 3D editing all day, but apparently not. In my first try I couldn't get even one. Practicing some more I got up to 4 in a game. I wonder if this game can distinguish between people who have rich mental imagery and those who don't?
You might have too rich of a mental geometry framework such that each shape was rendered more thoroughly, but not necessarily in a way that helped compute matching objects.
When you don't know the shapes, you have to do lots and lots of comparisons since you don't know what info you're missing behind the shape.
Once you do it a couple times, you can skip a lot of the conparison