Of course play testing is the preferred method for finding issue with mechanics, but there seem a few that could themselves present a problem.
Of course most of these have to do with Deeds.
Gunslinger Initiative: This isn't really as bothersome as some and is mostly a disagreement, but it doesn't seem much of a deed - you have 1 Grit, you get bonus Initiative and a special, but entirely pointless use, of Quick Draw. I say entirely pointless because if you have Quick Draw (a requirement for the "deed") you are already drawing as a free action and since it is only offered at initiative (ie, you don't get the bonus when surprised) you really gain nothing. Effectively all you get from this is a free bonus to initiative checks almost all the time. I can't put my finger on the problem, but the whole thing just rubs me the wrong way.
Pistol Whip: This represents a much more troublesome ability. Spent a point and get to use a firearm as a bludgeoning weapon you are proficient with? Great idea. On hit, try to knock target prone? Not so much. Do you get an attempt to knock a target prone with a normal hit from every other bludgeoning weapon? Maybe on a crit or at the expense of another grit.
And is this the same CMB as for a Trip attack? Do they get bonuses for being extra sturdy or anything similar?
These both go together really.
Covering Shot: I really see what they are trying to go for here, but I feel it's too strong and doesn't make sense. A miss causes a creature to be entangled? I can totally see how going for an established condition is the best way to go, but I just can't see it working. Some one gets shot at, so they move at half-speed, take a penalty to attack rolls and a penalty to Dex? Wouldn't that be the result of getting shot at regardless, hit or mess? Especially hit. Hell, wouldn't that be the result of getting hit ever?“Oh no, he shot at me. I wish he would have hit me instead so I wouldn't be afflicted by all these horrible conditions.”
Startling Shot: There are two differences between this and Covering Shot. (1) This causes the opponent to become flat-footed (2) It always occurs (as long as you have 1 grit). That just makes Covering Shot make less sense. When missed, he will be so scared that he loses his Dex bonus but maybe not so scared that his movement isn't hampered? I know what they are trying to do for both of these, but I just can't see it.
Since the idea of Covering Shot appears to be to distract the target, I would say have the Gunslinger spend a grit point and fire, but automatically miss the target (or hit some arbitrary AC) and THAT causes the target to become Entangled for a round. Similarly, I don't like Startling Shot being automatic flat-footed one a miss as long as you have a grit. I guess it isn't as much of a big deal at 15th level, but still. I can't think of much else at the moment to do with it.
Targeting: The problem I see with this is everyone is almost always going to choose Torso as soon as they get this ability. Assuming they have the grit points to spend. Now that I think about it (luckily) does this or does this not stack with Improved Critical?
And Scoot Unattended Object just confuses the hell out of me.