I think Caught Red-Handed is wrongly designed weakness. The effect commonly make the player angry. Why? This has two main effect:

1. Ready each enemy at your location or a connecting location.
2. Each hunter enemy at a connecting location moves 1 location toward you.

However, the discard condition only refers "second" condition. Even if the first condition met, Caught Red-Handed is returned to the deck after making all enemy ready. Notice that it's very easy to meet first condition; whereas it's rare to meet second condition.

Finn has free evade action. Thus, it's very common that he has Pickpocketing. After he evade an enemy, he trigger the Pickpocketing, and draw card. What if that card is Caught Red-Handed? Just evaded enemy is ready! In general, no hunter enemy moves so that Caught Red-Handed is returned into his deck. Now, Finn wasted evade, card. However, the weakness is still in deck.

Captivating Discovery is one of the fascinating card which is spoiled in scarlet keys. This provides the 6-cards searching effect, which helps to trigger the Astounding Revelation. In addition, this gives the 2/4/6-card drawing effect among 6-cards, which is powerful search/drawing ability. Someone might think that dropping the clues is expansive cost. Unlike other clue dropping cards such as Forewarned, however, the player can easily control the timming of the playing Captivating Discovery because the drawing effect is independent to the location. Thus, you could select the location to drop the clues. You may drop the clues at the location with low should value. You may drop the (unnecessary) clues at the location with non-victory location. It means that the cost of "dropping the clues" for Captivating Discovery is commonly lower than that for any other cards.

Just going to drop the Additional Cost ruling here. In particular :

Additional costs do not have to be paid when a Forced effect or mandatory instruction (such as in the Campaign Guide, or on the back of an Act or Agenda card) requires an investigator to resolve an effect.

So if you were torn away forcibly from or to the location with the barrier, you just go. You are not forced to test, and therefore you cannot get to the discard/milling/cancel movement clause. e.g. You cannot use this to your advantage to purposefully fail the test and choose "cancel the effects of the move" to refuse to go/move away. (I did that in one play, kind of amusing the investigators are holding onto the barrier that was harming them earlier, lol)

Disclaimer: Pre-Scarlet Keys release review.

Another niche card that is a bit hard to understand for now. Tactic is one of the least interesting Trait since it only matters for Mark Harrigan but he already accesses 0-5, Chuck Fergus (so "Skids" O'Toole) but it's already fast and doesn't involve a test, Directive - Red Tape but again it's already fast and Sleuth but it's probably one of the least interesting 3-class talent.

So, why would you ever use this card??

The main issue is "At the end of the round", meaning after the enemy phase.

• Daniela Reyes can automatically evade an enemy with her . Trigger it with the Mechanic's Wrench and attack with it, applying the wound. Since your turns are often a bit empty, applying a DoT to an enemy and leaving to engage another one is potentially really good. And on top of that, lvl 0 cards are not so hard to slot in her.
• Survival Knife (0) if, for some reason, you are already considering getting some hits, you can now do so with a 3-hp enemy and kill it after you get attacked. It's not great, but if you planned on taking the Survival Knife already, then it's worth considering.
• Butterfly Swords allow you to perform the first attack on an enemy and the second on another one. So you could technically do the smaller attack combined with Grievous Wound on a bigger enemy and the 2-damage attack to defeat a 2-hp enemy and evade the wounded enemy. That is a veeeery niche situation since it requires you to have 2 enemies in play, one that justifies this and that you are able to evade after... Let's see what other cards come in this pack. As of now, I see an opportunity here, but not enough yet for something viable.
• As suggested in the comment by @Veronica212, "Skids" O'Toole could be somehow a bit interested, as he is more able than others to evade and leave the DoT behind. Cheap Shot (2) is a good way to add 1 damage and exhaust, and Switchblade, Enchanted Blade without using a charge as suggested. It doesn't save you much time unless you can change location and the enemy is not a hunter.
• In the same vein, William Yorick could see use with Stunning Blow, attacking with a Gravedigger's Shovel, Fire Axe without going down to 0 resources, Meat Cleaver without spending the Horror, etc... The problem is that you need both Stunning Blow and Grievous Wound in your hand at the same time, which can be complicated with the little Draw ability of Yorick.
• Honorable mention to Trusty Bullwhip would have been nice with this since you can attack, exhaust to evade and apply the bleeding.

Conclusion: As of now, except for Daniela Reyes, I wouldn't really consider this card yet, but that may change in the near future!

Disclaimer: Pre-Scarlet Keys release review.

This is quite a niche card. For it to work, you need a Firearm, of course, but also to be spending your latest Ammo, while still having at least one fight action to take.

That being said, I believe that we can all agree on the fact that Vicious Blow is a must-have lvl 0 card for any main fighter Deck that has access to it. So if you pack at least 4 Firearms in your Deck, meaning you will use One in the Chamber at some point, how do these 2 compare?

Vicious Blow is simple: +1 , +1 damage on success, since you add it to another Attack.

One in the Chamber is fast, adds 1 Ammo, to your gun, which means at least +1 damage to an attack that would have been performed with bare hands, and +3 .

Results: Vicious Blow saves you one action only with enemies that have odd health, when One in the Chamber helps better (more ) with 4-health enemies and bigger, or if you are playing with 3-4 investigators and there are higher chances that you have to deal with more than 1 foe at the same time.

Compared to Extra Ammunition, you obviously get 2 less Ammo, but it is fast (meaning no AoO), and gives you a significant boost for the next attack, provided that you attack the same round. I see One in the Chamber like a great placeholder for Extra Ammunition for at least 2 thirds of the campaign.

The Firearms that are happy to have One in the Chamber are:

• Shotgun/Sawed-Off Shotgun/Old Shotgun, one more round, and plenty more reasons to make a good use out of it... If you didn't annihilate the enemy with the last shot fired. Worst case you add a bullet but do not benefit from the +3 .
• .41 Derringer/.41 Derringer (2), Mauser C96, Beretta M1918 for the Succeed by X
• Lupara to take better advantage of that one bursting round.
• The big performers like Flamethrower, Lightning Gun, Springfield M1903, Old Hunting Rifle.

The happy users are: Leo Anderson/Tony Morgan/"Skids" O'Toole that have access to the "Succeed by X" guns or tend to also purchase massive Firearms. After that, any that is tempted to run the Shotgun like Sister Mary, Mark Harrigan, Holy Shotgun Tommy

Conclusion: Fair card, will see use in certain Decks that plan on using the Shotgun, or the set of Succeed by X Firearms. This will most likely be a placeholder for Extra Ammunition, which makes the upgrade a lesser priority.