Pretty amazing. I never trained him to open doors but I did notice that
he kept watching me open the room doors then one day I was watching TV
in the livingroom and I hear a door creaking open. I thought it was a
burglar until I saw a sillouette of a cat running to the kitchen
cupboard (where the food is stored), I did not belive it was possible
so I figured maybe the door was left ajar.

Well today I was in the room and saw him do it. He stands as tall as
possible and pulls down on the lever and slightly pulls back to get the
door ajar (the doors open by pulling back not pushing) then when the
door is ajar he sticks his paw underneath the door and pulls it open!

To prevent him from doing this I put some tape on the lever so that
pulling down would not work only pushing up. For a while it worked fine
until he figured out that breaking the tape (by jumping and tearing it
with his claws) and then using the lever again. I had to remove the
lock and will be buying a regular doorknob. Although I left the lever
doorknob in the office (I plan to videotape this)

Now he also knows how to open cupboard doors also after trial and error
experimentation.

Is this normal? Are all cats this smart? My dogs are totally dumb
compared to the cat.