They're just alternate endings/retellings of the series. So they really are best to watch after having seen the whole thing. That way you can compare them to how the show actually played out. Technically speaking they're the "original" versions of the story that didn't end up how Shiro Kanzaki wanted them to so he rest the universe a couple of times.

I'd say Episode Final is worth watching if for no other reason than Femme is the best movie Rider ever.

Episode 27 of Agito was probably one of the best child-centric episodes of any kind of show like this.

I had to look that up. That's the one with Ryo and the runaway kid?

Yeah, that one. It's a good episode.

Honestly, I see nothing to support this outside of it being fan speculation.

I haven't seen them in a while, but doesn't he end each one with a narration over it being wrong?

Not the movie. Maybe the special, as I haven't ever seen that thing subbed.

That sounds about right for 13 Riders. It's been awhile since I saw it, though - it's not all that great, even if it is the only place to see Verde.

Watching Kamen Rider Black right now, very cool stuff.