There's a glitch with the glass hammer and the piggy bank, if you hit the piggy bank with the glass hammer really hard it turns into glass and has no collisions but won't break or disappear.
I have an idea for a property. Maybe it could be called "Corrosive". Anything the object that has this property touches another object, it will get acid on it. Does that sound like a good idea?
See FAQ. Basically the game's rendering is done in a stupid way (yay me) so it doesn't work with zooming.