Eric writes about his last two one-shot RPGs at Talking Game, both of which I played in. He describes feeling unsatisfied with the first, a game based on Katherine Kurtz's Deryni novels and using the FUDGE rules system:

The game was ... okay. The players weren't as into it as I'd have liked, and my usual off-the-cuff GM-ing style didn't seem to work. I had fun, and (apparently) so did the players, but I was left feeling a bit unsatisfied. And I didn't get the enthusiastic vibe from the players that you can get after a good session. It showed a lot of potential - and I'd definitely be willing revisit the game for a sequel at some point - I deliberately left a few plot hooks dangling - but I suspect that, if the players were filling out a report card, it would have received a B-minus or C-plus grade.

By contrast, he counts his CthulhuTech one-shot (which I also posted about) as a great success. I agree with him on both counts -- although I may have enjoyed Deryni more than he did. Here's why I would give the Deryni one-shot a B-minus grade, and why CthuluTech got an A-plus.

Setting

FUDGE: I just didn't grok the setting. I've never read Kurtz's novels.  I got enough information on its alternate, magical history from Wikipedia to navigate the adventure, but I had no sense of what I should love, hate, or want.

CTHULHUTECH: I'm a Lovecraft fiend, and also love cyberpunk and anime. I immediately recognized this world. I knew who I was in relation to the setting, and where to go from the starting square. But I suspect that even if I wasn't familiar with those genres, I still would have had a better time banging around the world of CthulhuTech, because this is an easy premise to digest: "The world is under attack by horrific aliens who are secretly served by corrupt humans, and they will probably win. Your job is to fight them."

Character

FUDGE: Rather than pre-generating characters, Eric asked us what sorts of characters we would like to play. I chose to be an itinerant healer with lofty ideals. This turned out to be a poor choice from a role-playing perspective: he had no real motivation, or conflict, nothing I could sink my teeth into. I didn't know who I was, so I didn't know how to respond to what was happening in front of me.

CTHULHUTECH: Eric gave us our choice of characters consisting of stats, skills and two personality descriptors, and that was exactly enough for me to run with. Police officer Patrick "Vader" Sullivan was a bad guy on the side of the angels, a violent man who shamefully tormented those weaker than him, but who would fight to the last for the survival of humanity. So perhaps I do better when I'm given several concrete options to work with, along with the freedom to add my own contributions to the character.

Plot

FUDGE: We were tasked with solving a mystery, recovering a missing item, and foiling some bad guys. We did these things. But when I looked at my fellow players and at the GM for confirmation that we'd won, I saw blank looks all around. We actually debated whether the adventure was really over. Eric said we could keep going if we wanted, but there were no strong storytellling cues that shouted, "More adventure THIS way!" So we sort of wandered off into the sunset.

CTHULHUTECH: We were tasked with solving a mystery, recovering a missing item, and foiling some bad guys. We did these things, and knew when we'd won. Part of it was that the GM had ways to help us along when we went astray, in the form of trusted NPCs. Part of it was that at the end, most everyone who needed killing or arresting was killed or arrested. Some got away and some went undiscovered; but the noir/Lovecraftian setting leads players to expect the worst, and accept the inability of human beings to deal with some levels of reality; so we were satisfied with having achieved something. ("It's Chinatown, Jake," I muttered to one of my fellow officers. I don't know if anyone got it.)