Ha, pretty cool, I would've never thought to create an RP story like that. Very nice job. If you don't mind, though, I have a few constructive criticisms. 
Things that, in my opinion, could've made it better;
Letting the viewers get to know all the members of the group, and their relationships with Dark Lightning. Make us want him back as badly as your group does.
Giving us more background information on when DL dissapeared, and why. Maybe even some lead-up slides taken before DL goes missing to set the stage.
More dialogue slides, maybe even some comic-book-style close up slides on the action as it happens, rather than the before, after, and during shots that you took.
Other than that, though, I commend you on putting the work into something like that, and I enjoyed it. 
Seeing as how your group isn't into RP like you mentioned, you did a very nice job of orchestrating their dialogue and the screenshots. I especially liked the one with the trolls knocked out in a circle around your character.
Agreed, not knowing the characters makes this odd from an outsiders view. We didn't really have making this in mind but when we started I started with the screen shots and got the idea to put um together afterwards. Maybe on the next one we'll orgnaize it. 
We did a first attemp at RP a few nights ago. I'ts a spoiler so if you are in the FRONT and might be doing this then dont look at this. Download this slideshow and rename to exe and run (on windows systems).
Most of the group had no idea what was going on. And they aren't really into RP. But I think it came out interesting.
I made this very late at night and didn't spell check it, so please ignore misspellings.