Really awesome.
Robust (you can drag it around with some force) but breakable.
Maybe it's too macabre with a dog, but if you could make a human one and add some flesh with skin that is robust (not falling off when you stab through it - like in "eye removal machine"), you could get into the top scores.
"Really good except it doesn't loop on to the otherside like the real one. "
I don't understand what you mean. You have to press the enter key for a short time to get to the next generation. If you hold it for too long, there are bugs.
If you continue this, it will behave exactly like the real one.
You should make everything except the guys immortal (immortal = true) and only make things red that are not immortal when they collide with the spikes.