Chapter 1: A Short Trip to Yesteryear
Past-Ralph isn't confused by seeing himself. He's the kind of guy who expects to bump into himself at a different point in his own timeline at some point.
The atomic de-stabiliser is not Chekhov's Gun. It's Ralph's, duh. Also I made it look a little too much like Spider Jerusalem's Bowel Disruptor from the excellent Transmetropolitan, not that Ralph's ever built one before. Oh wait, he did.
Fun fact: Past-Ralph's hair is a little bit fuzzier than Present-Ralph. I used the "fur" tool on it like I used to back in the day.