Hee, I really liked this one!
I love love love old school cartoons, and it was so much fun to see all that cartoon logic in the "real" world. I guess my favorite moment was probably the gun going BANG. Or maybe the talking cat, because I'm a crazy cat lady. It was all pretty entertaining, and I actually laughed out loud a few times. Awesome. :D
Another thing I liked was how they brought up John a few times throughout the episode, and that the case included one of his old contacts. It's such a small thing, but I feel that the show sometimes forgets Sam and Dean actually had a dad, so that was nice.
Now, my favorite thing about this episode? Sam flashbacks that were insightful and emotionally satisfying. I'll admit I wasn't expecting it, because seriously, they went from Cas sniffing a bladder infection to the first flashback, and for a second there I swear I was like, "great, Sam had a bladder infection while Dean was in Purgatory". Anyway, I'm rambling. Point is, I've been waiting for something like this since the season started, and I felt that tonight Sam's storyline started making sense to me.
I love that Amelia's dad totally saw through him, and omg it was so sad when Sam was talking about Dean. I also like how that tied in with what Sam said in the end about running away. What I took from it was that Sam eventually realized hanging on to a 'normal' life would never be enough to fill the void left by everything and everyone he lost, particularly Dean. No idea how that's going to play out with Amelia's husband being alive and all, but hey, that's a Sam I can understand.
So yeah, overall I thought this was a very satisfying episode, and now I'm a little more excited to see what will happen next. :)