As to the gun, I thought he said he heard a sound (Ryan getting into the shed and taking the gun) so he went out, to the shed for the gun for protection and it wasn't there. Then a few days later, when he went back to the shed it was there..
Then there was the whole security camera footage.
First scene, it is hooked up, but doesn't seem to be recording.
Later, he apparently got it going, but doesn't think to check it (Mare does over the graffiti, which she then promptly deletes a file of some random neighbor kid doing the graffiti).
Then, finally, when he calls Mare over and she starts scrolling back and discovers Ryan on it.
Additionally, shouldn't this have been the same day of the murder? (Frank's engagement party, Mare's basketball anniversary) I'm not saying it's out of the realm that he instantly fixed it, but when Mare scrolled back there were additional files before the one she discovered Ryan in (there was nothing there the first time she looked).
They did seem to weave some unnecessary things into the show. I thought for sure that Richard (Guy Pierce) was the killer. Why else did they introduce the character and why such a well known actor? It turns out it was just to go on a date with and have sex with Mare one time. And why did they have Detective Zabel crush on Mare? That was a little strange to me.
Richard was fine. He provided the bf character that fleshed Mare out more and give the hint of "could he be the killer?"
Some of the things they did with Dylan didn't make sense, to me, other than "let's make him seem guilty with none of it making much sense". Why did he leave in the middle of the night? Why was he, his friend, and Erin's friend so hellbent on getting the journals? If he didn't kill her and had no suspicion about the fatherhood, why get the journals and burn them without reading? Why let the friend sit in a window sill reading them when you already agreed to not read them?
Did I miss something here or did they cut a scene explaining the motivation? Or was this just about pushing the "Dylan is guilty" idea?
Also, they gave us the scene where John told his wife Billy had killed Erin. Then later when she explains it, he actually told her that their son had done it. What changed? Another scene that conveniently leads the audience to the wrong guess, but it was a present moment shot; not somebody recounting a situation (that would have worked better in the scheme of covering up for Ryan).
I really need to watch the show again.