Others have pointed out this card's inherent clunkiness and I'm certainly not going to argue against that. It's definitely a weird card, but it has some some surprising flexibility, too. It's an interrupt, and not specifically a hero or AE interrupt, so it has some extra value with heroes that like to flip a lot and get allies on the table. X-Men and Guardians both have cards that encourage ally swarms/mini-voltrons even in aggression and Gatekeeper can be nice for letting your beefed up allies contribute to thwarting while keeping the table clear of minions. I know some earlier reviews compared this to Chase Them Down but I think there's a better comparison to be made with War Room. War Room has more flexible scheme targets, but Gatekeeper can be triggered by any hero or ally and it removes a much higher threat value (albeit only from the main scheme).

Others mentioned that it potentially has more value in multiplayer and I think this is where the card really shines. It's a great "side board" card. A dedicated thwarter will make this card obsolete, but 5+ years into the game, not every justice player wants to be a dedicated thwarter. A copy of this card in your deck can contribute to keeping threat low with a wider variety of other decks in multiplayer. Hard to recommend building a deck around this card, but it can be a decent flex option.

One of the best cards in the game. 1 ER for a completely blocked attack is bonkers. Ronan attacking for 7+? No problem, just throw this card down and get out of the way. Spider-Man also gets to draw a card when being attacked so his hand size will remain at 5 when playing this card.

Rating: S (S-D)

Ran this recently in my Tigra and was able to easily play them with her resource generator Cat's Head Amulet. Three Beat Cops, coupled with Precinct HQ and I was removing 6+ threat on my Alter Ego turns. With a few allies, threat becomes no issue, and you can focus on burning down the villain. Definitely a turn 2 or later play, almost never playable on turn 1 though.

Not every Player Side Scheme is great.

This one though, if you are playing an X-Men deck in leadership, is pretty good.

2-per player is a pretty low bar for threat; if you are playing solo this is usually going to be a single thwart (for the majority of heroes). It gives everyone at the table a 2-cost ally with a 2/2/2 stat line which is already great. Sure, it doesn't put them into play; but you have that ally for the rest of the game.

And if you are playing an X-Men character, the ally gets a boost which is pretty powerful. The person who put the PSS out has to be playing an X-Men character anyway, so it's only other players who could get the "unboosted" version of the ally. And the boosted ones are really good - 3 attack or 3 thwart, on a 2-cost ally? Or an ally with 2/2/4?

And if you are playing Leadership X-Men, you probably have Uncanny X-Men out - a 1-cost ally with 3/2/3 stats? Yes please!

Unless you are really hurting for card space, this is a great add to any X-Men hero running Leadership.

Note also - with Children of the Atom, X-Force heroes can get in on using this too.

Best card for Phoenix .