only got to the third kept messing up the boxes I assume you need to get one box to the the top area after going to the left all the way then up and a platform to the right even had one box get stuck under the door which made me have to restart the level.
I wonder if using the right hand like the right Ctrl and shift would be easier on then z and x for changing from cold to hot. Might be nice to have a outline of the object that is not shown as well but that might make some areas to easy. Good game though.