Orange your eyes can open slightly when in a deep sleep. My dog used to sleep with it's eyes wide open. It looked dead save for the fact that you could see it breathing.
OT: only (minor) issue i can see is a bit of banding but it's not very noticable.
The "Zzz" doesn't seem to coincide with his eyes.
I mean you don't usually snore with your eyes open.
Thanks for the comments!