My second test for the convention was from the same publisher as the first. This went much better. Interestingly, both games use the idea of a spinning board. Which is fine. I imagine most designers have a pet mechanic or two. myself included.
Planet 313 is a family and hobbyist-oriented dice-allocation game where each player is trying to move his or her spaceships from his or her corner of the board to the center planet and is aimed to last about 50 minutes. The board is made up of concentric, independently-spinning rings. Each ring has spaces on it. On your turn, you draw a card and roll four dice. Two represent movement points (1-4), one determines which ring gets spun clockwise and the other how many spaces it is spun. You can either combine movement dice for one of your ships or split them between two ships. The hitch is that it costs an exact 4 to move your ships from one ring to the next, unless you start your turn on a space that allows cheap movement inwards. Launching your ship from your base into the outermost ring also costs an exact 4. Let that rule roll around in your head for later. Battle happens when two ships land on the same spot. it's mostly random based on the cards you have in hand. Losing a battle sends your ship back to base. There are also event cards you can play that switch ships around, move them back, or send them back to base depending on various random conditions.
So, if you have though about that launching rule for a bit, I'm sure you can guess what the biggest problem with this game is. It is entirely possible to go many turns in the game without being able to do a single thing. Now, all you dice-lovers out there will say, "Michael, dice even out over time." To which I reply: Dice aren't magical devices that ensure an even distribution of luck. Reliance on the law of large numbers is terrible design.
"Michael, you dice-bigot, sure, HYPOTHETICALLY one person could have worse luck than others, but that's very unlikely to be a big deal." Hypothetical-schmypothetical! One of the four players in our test went 10+ turns without being able to launch a single ship! And the only reason that ended was I felt bad and played a card on him that let him launch a ship for free. Now, a rational player would never, ever do that. But by this point it was clear to everyone how broken the game was so I didn't care. And, of course, his one launched ship was almost immediately destroyed by some random something-or-other.
Designers: you HAVE to design for the long tail of your probability distributions. One player going for half an hour without doing a single thing to affect the game is called bad design. It's also called wargaming. Badum-chisssss!
Despite that major oversight, I think this could turn into a fine it-is-what-it-is game with enough tweaking. It could never become a game I'd personally like, but I can see the foundation of the sort of thing dice-lovers would eat up as a light game.
A note about the components. I don't know how they would have produced a retail version, but the prototype was a series of increasingly-sized discs, with the smallest disk stacked on top. This made spinning one disk by itself a non-trivial task, as it meant your had to physically hold the two neighboring discs in place while spinning the one a certain number of spaces. If you're designing a game for children to play, make sure that they can perform the physical tasks required to do so. I can see a 7 or 9-year-old having difficulty with this manipulation.
Still, this was far better suited as a family game than the previous one and the problems should be quite easy to iron out. I wouldn't be surprised if this was brought to market within a year.