Sawed-Off Shotgun. You can shoot two players sitting next to each other with one BANG! as long as both players are in range. This card and its description are thematically appropriate. It is similar to the "Scatter Gun" event card in the O. K. Corral, but has range stipulations. I prefer this one.
The Old Switcheroo. Immediately after phase one, you can exchange your cards with any other player (all for all). The description fits the card name, but I think this card is OP and messes the game up too much. It really favors the Outlaws who can swap an offensive hand for all of the defensive cards in the Sheriff's hand, and then the other Outlaws can pound him with attack cards. And small hands can trade for bigger ones too of course.
Prison Break. All prisoners are now free. The player(s) that imprisoned them must play a Missed! card or lose 1 life point. If no one is in prison, players must defend against an escapee by drawing! ♠ = hit. This card is thematically good and the conditions are great, accomodating the fact that very rarely will this card be in play when a player is in Jail. Good.
New Sheriff in Town. If you are a deputy and kill the Sheriff, you become the new Sheriff. You get full health and all of the Sheriff’s cards (those in his hand as well as those in front of him). I don't like this card; it has very little utility. The only time I can imagine intentionally popping off the Sheriff as a Deputy would be if he had almost no health and no cards. Otherwise, why would I want one less ally on my team? This card would make more sense if the Renegade killed the Sheriff, but even then, the chances of being able to off the Sheriff in 1 round are very unlikely. I would nix this card.
Iron Will. Each time you are about to lose a card from your hand or in play in front of you, you can choose which card to lose. Fun; very few people will use a card or ability that discards/steals a card from another player this turn, but it is an interesting concept. It will at least keep people from discarding/stealing a card for a round (unless there is only 1 in the hand or in play in front of another player), so it is somewhat useful. Okay I guess.
Kaboom. If you have a dynamite card, you may chose where to start it. It is in play when that player begins his turn and explodes (for that player only) if that player draws! any ♠. I think it is very unlikely that a player will have a Dynamite saved up in his hand coincidentally or waiting for this card to show up. Don't like it.
Mother Load. At the beginning of your turn, you may use any card as a General Store. Instead of other players picking their cards, you decide who gets what. I imagine you get to play any card as a General Store, do so only once, and then get to draw your normal amount of cards. The General Store plays like Claus the Saint's ability, minus the fact that Claus draws 2 (+1 card added to the General Store). This card could be interesting; I would have to see it playtested.
Quick Draw. You can play cards with the ‘add one more card symbol’ without having to add another card. The idea behind this is cool, except that there are only a few cards that require adding one more card to play them, and it is not likely they will be drawn during this round. So this isn't the best event card in my opinion.
Returning Fire. Each time you are hit, you draw—on ♥ or ♦, the player hitting you must play a Missed! card or lose 1 life point. Like this card a lot, except I wouldn't make it a Missed! card, but playing or using any card with a missed symbol on it (including Barrel).
Gypsy Rose. You can look at one other player’s hand. I'd have to see this card play tested to know if it was OP for some roles or not. You could limit it to a set amount of cards in someone's hand to nerf it some.
Green Flash. You can play green bordered cards immediately. While this should say "use" the cards immediately, I like the idea. "Green Flash" is a pretty hokey name for this, though.
Hazard. When you must draw! (dynamite, prison, barrel, etc.), you can discard a card from your hand and use it as the result. This takes a Boot Hill character's ability--Matthew Hazard's--and grants it to everyone for the round. Interesting idea. The title is somewhat confusing, as few people will actually know about Matthew Hazard to recognize the connection.
Poker Hand. Select up to 2 cards from your hand and then draw 3 cards. Player(s) with best hand regain all life points and keep cards. All other players discard their poker hands. I get the idea of this card, but the gameplay is a little confusing. Must all players participate or is it completely optional? It is hard to prep for a good hand when you must select the cards before you see the flop, making the outcome far more random. That could be good or bad. The reward is somewhat obscene though: gaining all of your health back plus the cards. This card needs some rethinking.
Spit Shake. You may give any player one of your cards. That player must then give you one of his. He is allowed to give the same card back. I like this card a lot; well done.
Peeping Tom. At the start of your turn, you draw! If you get a 2-9 ♥, you may take a peek at the role of any other player. This card is terrible, like the Search Warrant in O. K. Corral. Roles should not be directly known until a player is dead and the role card is flipped over. It kills the whole mafia intrigue of the game, which is central to BANG! Boo.
Outlaws Unite. The Sheriff narrates the following sequence: Everyone closes their
eyes. All outlaws reveal themselves by opening their eyes. Outlaws close their eyes. Everyone opens their eyes. As with Peeping Tom, I hate this card. Role-revealing is stupid, and this card is even worse because people can cheat at it.
Rapture. The first person to die is granted the option of becoming the Sheriff of the next game. This card is interesting, but it doesn't make sense as an event card. This should be a house rule instead.
Indian Poker. Everyone draws! a card and holds it to forehead facing out. Each player discards or holds. Highest card wins and gets cards of losers who must discard all hand cards. Order: A♥-♦-♣-2♠ This card is too strong because all losers have to discard all the cards in their hands. It would be better if the winner just gets all of the cards. If you discard you only lose that 1 card, and if you hold, perhaps the winner gets to take one card at random from your hand.
The Peterson Pack is a double-edged sword; while certain event cards it adds to BANG! are fantastic (Green Flash, Spit Shake, Returning Fire, Prison Break), others are impractical (New Sheriff in Town, Kaboom, Quick Draw) or unacceptably ruin the game's deception dynamic (Peeping Tom, Outlaws Unite). I can imagine keeping some of the cards from this deck and combining them with some of those in O. K. Corral to get a higher quality custom event card deck.
The cards in the Peterson Pack are written pretty clearly, despite some grammatical problems, and they have a very consistent (although bland) format. The problem is more in what gameplay effects they create, not as much in how the cards are written. Theme is followed pretty carefully throughout, but I can't give it points for novelty. Yet it has the best ease of production I have seen for a custom expansion!
Gameplay Enhancement: 2.5/5
Ease of Production: 5/5