So in last night's game, the continuation of Twisted Fifties, the PCs arrive mob-handed at the asylum to confront Dr Scolari, the twisted woman hater who seems to be at the root of all their problems.

Scolari is in his office but this doesn't deter Gandolfini, the brutish mobster who busts right in, with the PI and the hooker on his coat tails.

Scolari sics his goons on Gandolfini who defines the magical fact that his gun allows him to summon up the spirit of anyone he's ever killed with it and command them (the price: they get to give Gandolfini an offer he can't refuse). That keeps the goons occupied whilst he goes for the Doc.

Scolari pulls out a syringe from his drawer and I give him the fact that he never misses with it. The players hit back with the price that this causes several minutes of physical ecstacy in the good Doc who can take no physical actions when thus enraptured.

So mechanically, the Doc only needs spend one token to hit Gandolfini and spends the rest dodging the hood's bullet, which nicks him anyway. Scolari collapses wounded and enchantment by not only sticking it in someone else but also by the blood loss. The hooker's attempts to strangle him just push him all the way to erotic asphixiationy bliss.

But Gandolfini is medicined good and sees a magic bear arrive with a special cloak of escape for him. Gandolfini accepts the cloak and is taken, straight-jacketed down to the cells.

So, my question is, "never miss" might seem like a rule-breaker. Do you consider this within the spirit of the game? I mean, it worked last night so that was fine but I'm looking for more general definitions. How far can you go with a magical fact?

I think that the only limit on what can be established as magical fact is the theme document and the other players around the table.  Since the person declaring "Never miss" as a fact doesn't get to set the price, their opponent can declare a price that makes it hard to decide when to use the power.  If a player wants to establish that a certain wizard PC can draw a gun and always hit, then the GM gets a chance to say "But the wounds dealt by such a magical blow are reciprocated upon the user."  It will make the player consider twice how badly they want to use that power, if shooting a guy in the leg is going to give them a shattered femur as well...

I'm with dyjoots on this one. I think "never miss" is legit, so long as it fits the theme document. However, for an ability of this sort, the price ought to be pretty high. It's a matter of whether or not the group agrees that some power like this is possible. Of course, it seems to me that you can "never miss" and still only do a scratch to the target character (with drugs, like above, that's not such a big deal).

Also, I'm not clear if this effect is applicable to all syringes, or just this one?