Why do we not have a review for this card yet? It feels like the elevator pitch writes itself.

Commercials aside, the interesting comparison to make is against House of Knives, the original 3/1 agenda that has made its way into many a Jinteki deck:

  • Knives does a total of 9 damage when all 3 are scored, spread out over several turns. Runs are more dangerous to do while there are still valuable cards in-hand, against ICE like Komainu, or when stealing that final Obokata Protocol, perfect for grinding down the Runner's stack and options over a long game. Best scored early, to slow the Runner down and get those pings in.

  • Sting does a total of 3 to 5 damage (best case 1, 1, 3 or 1, 2, 2) in larger chunks. This is perfect for setting up proactive flatlines since this burst damage can be done clickless for a future turn, similar to Ronin. And if enough copies of Sting are scored, this turns into a Gene Splicer where you got a good chance of giving the Runner no good options to steal it, threatening flatlines on follow-ups.

So which agenda do you put in your suite? That mostly depends on what the deck is trying to accomplish.

You can't go wrong with either, but I feel decks aiming for a flatline will want Sting! for more chances at landing that killing blow. Decks that want to slow the game down early while seeing an empty stack late game will want House of Knives. Of course, you can always take both since they are doing different jobs.

And of course, you can't talk about Sting! without talking about the ID this sits most at home with, Personal Evolution. It's a bit scary how good this agenda is in there, making both defensive and offensive uses of the scorpion all that much more lethal.

Long live the scorpion.

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Excellent review. Long live the king. —
Since the damage keys off the other player's score area, you can't do 1-2-3 without shenanigans; best case is 1-2-2 or 1-1-3. —
Thanks for pointing out that small mistake! I've updated the review to reflect that. —

This is a strictly upgraded Melange Mining Corp. Coming at a rez cost of 0 compared to 1, it yields 6 credits instead of 7. This makes it an even gain on its first use after rez; additional uses will yield one less credit compared to Melange, if you can manage it. Each use will additionally allow the corp to remove 1 Bad Publicity, which has been a rare effect up to this point. To cap it all off it has a trash cost of 3, raised from 1.

Liked your review. But "strictly upgraded" is an exaggeration. —
It's "strictly" an upgrade~ish if you're in Weyland. If you're not in Weyland, it's a similar effect to Melange at 1 Inf a pop. If you're removing 1 Bad pub each time you fire this thing, then you probably don't care that the subsequent uses gain 1 less credit than Melange. The +2 trash cost is also welcome. If there's no bad pub to remove, or if you're not in Weyland, then there's still an argument to be made for Melange. —

I usually slot one of these in my Jinteki decks because I found it very versatile and useful in several ocassions. For glacier or horizontal jintekis. By these days I use it for the following

  • Put a used Snare! in my hand. Install the same snare and an agenda.

  • Make the same trick with an agenda as Fetal AI or Obokata Protocol if I haven't avanced them yet. Or if I have just drawn the Mushin No Shin to play them next turn.

  • Put the Snare in your hand and make your hand more scary. Install ice in other places.

  • Avoid Femme Fatale tokens. Install the same ice or another one.

  • Remove a Mwanza City Grid that has been already useful.

  • Just install scary ice in a remote server with already lots of ice without paying anything.

I haven't tried to export it to other factions yet, but the Jinteki mind games are more difficult to import and with a 3 influence is harder to justify.

Gatekeeper is strongest when it was rezzed this turn, so it would combo with cards that allow you to derez your own. Cards that help you get more activations from the rez strength ability are needed to help combo.

Blue Sun: Powering the Future to replace this where needed, with another strength boost. (Thanks blackcherries)

The Foundry: Refining the Process can fire and get you more of these, with the help of other cards below.

Divert Power makes something cheaper while you get to trigger this rez strength again.

Test Ground allows you to fire the trash ability, derez Gatekeeper, and then re-rez Gatekeeper with unexpected strength.

Other combos, provided you were using them already

Isabel McGuire

Replanting

Plus, Gatekeeper is cheap and might give you some recursion of used cards if you can catch the runner flat.

Is it for every deck? No. But it might have a place in some.

(Edited to remove bioroid research reference and added blue sun)

Great first review. You've highlighted —
some good combos. Just note that Bioroid Efficiency does not work as Gatekeeper is not a bioroid ICE. In addition, Blue Sun is also worth a mention! —

Rules doubt.

Does lucky charm also work for any subroutine (for example a wall of static or vanilla)? Or just things that say "end the run" that they're not from the corp?

Are subroutines card abilities?

Yes, that is correct. It can be used against WoS or Vanilla or any other normal (single) ETR sub. —