The ones of the cat are definitely the best.
"CN88" bothers me because there is so much of the white, blown out sky in it.
"Door Drops to Track" has potiental but it's crooked and the fact that there's nothing under the door doesn't really jump out at you. With a shot like this, you want the persepective to really make the weirdness of the door pop out so it immediately grabs peoples attention. I didn't even realize there was something strange about it until after a few seconds of staring at it and I was only staring at it because I was looking to see just how crooked it was. Shooting it straight-on flatten it out, it might have been better to shot it more at an angle so people can see there's nothing under the door when you step out.
"Street Grate" just doesn't seem to have a subject. Is it the car? The people? The buildings? Whatever it is, it's too dark and you can't see enough of it.
The Cat photos... the first one has nice lighting but I don't find a yawning cat very interesting personally. The second one however is very nice. It's sharp, it has good lighting, good composition, and a great expression. I'm not too big on the title though.