The fact that this comes into play already loaded makes me think it's going to be great in WIlliam Yorick, if he can get the economy to pay for it. He can fire it, blow some poor schmuck to hell and back, then toss it into the trash as he pulls out some other sidearm, or a second Tankgewehr in its place.

Antikythera is the big Seeker card of TDC, and combos very well with a lot of previously released precision tech. For some flavor, an Antikythera is an Ancient Greek hand-powered orrery (model of the Solar System). It is the oldest known example of an analogue computer (yes I did copy and paste from Wikipedia...). This review is a bit of deep dive, you have been warned!

Pros:

• Rewards you for passing tests most of the time, with only a success by 0 or 6+ not providing any benefit (with the latter being unusual).
• The rewards help directly with scenario advancement (a clue on a 1 or 3), or your economy (a resource and a card on a 2 or 4), or whatever benefit you want (free action next turn on a 5). As a result, Antikythera is very likely to refund its cost if played early.
• Has generous icons, so running a second copy is not a dead card.
• The Accessory slot isn't too competitive in Seekers, and most of the other good accessories also cost experience.
• Has the Relic keyword, making it more tutorable.
• The Seeker class is home to many 'precision' cards which combo with it well and allow for success modification.

Cons:

• Costs 5 experience.
• It exhausts, so only useable once per round without support.
• The success by 5 benefit is arguably the worst one, compared to guaranteed clue compression or a card plus resource.

Deckbuilding tips:

• Success modification: The Seeker class is home to cards which allow you to modify successes and so achieve the result you want. These include Artistic Inspiration and Steady-Handed, as well as Inquisitive (technically not a Seeker card, but accessible to a lot Seekers). Cards like Analysis can provide do-overs for tests, and off-class cards like Daring Maneuver, Scrying Mirror or Olive McBride can help manipulate tests as well. For signature assets, Lucius Galloway's Book of Verse also manipulates successes.

• Precision tech: Seekers have access to a number of cards which benefit from success by specific amounts. Alton O'Connell benefits from success by exactly 3 that you'll usually want for extra clues on Antikythera (plus he's level 0 physical soak, not so common on Seekers). Steady-Handed, in addition to success modification, heals horror by a success of 2 - useful in a class which often cycles its decks. Less usefully there's Dr. Charles West III, Chemistry Set (accessible with Relic Hunter) and Correlate All Its Contents. Off-class there's Katana if you feel like getting creative. There's also overlap with the over-success archetype in Rogues (cards like Breaking and Entering ••, Pickpocketing ••, Lockpicks or Bum's Rush) where the threshold of over-success aligns with a succeed-by amount on Antikythera.

• Readying: There's a few cards which will let you ready an exhausted Antikythera so you can get additional uses in a round. Fine Tuning is the most noteworthy of these, and if running two copies you can attach the second one to things like Steady-Handed. Less usefully there's The Raven Quill with the Interwoven Ink upgrade, which allows you to ready another asset. Off-class there's Bulwark accessible to Joe Diamond, and Transfiguration to become "Ashcan" Pete for Daisy.

• Finding Antikythera: Whitton Greene or Whitton Greene •• are excellent for this, tutoring for Antikythera whenever you reveal a new location and providing an boost when it's in play (as well as providing sought-after physical soak). Given a choice between Whitton, Alton or Milan, I would usually choose Whitton as she boosts the stat that Seekers care about and helps you get Antikythera out faster - however it’s a matter of taste and running all 3 with Miskatonic Archaeology Funding is far from a bad idea. Other tutors (Mr. "Rook", Captivating Discovery, Backpack, No Stone Unturned and their relevant upgrades) can also help you find it.

• Increasing opportunities to test: Mind over Matter and Hyperphysical Shotcaster can help you test on a lot of different types of tests, increasing opportunities to trigger Antikythera for Seekers who slant heavily to Intellect. In terms of combos, Hyperphysical Shotcaster as a Relic is also tutorable by Whitton Greene.

• Investigator pairings: Lucius Galloway is a natural pick, having the aforementioned Book of Verse as well as high to provide opportunities outside of tests to trigger Antikythera (look, a deck). Joe Diamond similarly has high and so can trigger Antikythera both while investigating and fighting (getting clues while you kill things is always nice), and can use Bulwark for readying. Aside from Lucius, non-parallel Monterey Jack and Ursula Downs have high and so can trigger Antikythera while evading, and make better use of Alton O'Connell than some Seekers. Harvey Walters is worth a mention, as Antikythera can trigger his card drawing ability on a 2 or 4 success to provide 2 cards (which gives you fodder for Artistic Inspiration). I made a deck along these lines with Harvey and posted it just before this review (link here if you're interested). Realistically though, just about any Seeker will make good use of Antikythera.

There you have it! Antikythera is a very powerful card and useable on just about any Seeker deck - well worth the 5 XP cost in my opinion. Do you think it's too powerful, or just good fun? Let me know your thoughts, as well as if I've missed anything.

"Casual" way of use I found that won't require knowledge of exactly what's in the encounter deck is when you are already engaging, and you want to use 1 of your 3 actions to get 2~3 more cards without taking any AoO in order to get some event or skill card solutions. Unless encounter deck has 0 enemy, I think it is likely you can pick a 1/1 enemy so you can draw 2 cards to help with the current, more difficult fight, then deal with that thing the next round. You can also look at discard pile too.

An example of in-box combos, cards like Robert Castaigne (4) require materials on hand to go ham with his and "Where's the party?" draws might be just the right thing. If you are with Dakota Garofalo instead, maybe you can get her stat boosts on along with using the draws. Drawing into Bum's Rush or Elusive isn't bad either if you are looking for a way out in the first place, because either you or the enemy is then displaced to balance out the fact that you just increased amount enemy on board.

It's a test on enemy's health therefore its niche is to get rid of 3~4 HP enemies in one action where otherwise it makes your action / ammo calculation worse to clear the board, or you really need to not cause friendly fire or skip Retaliate / Aloof by the Parley. You will often not want to whittle down enemy's HP from its max value to make the test easier, because then you can finish it without costing 3 resources on this card. On 3 HP enemy it competes with Backstab which uses and can hit friends.

But when I was trying to use this, it is more often that I can clear the board with the combat stats required to use this card in the first place, and rather save 3 resources than ammo or actions. Even Michael McGlen wants some commits to intimidate enemy with that HP to not waste 3 resources, while his gun provides some built-in boosts. It ended up too much of an investment.

The Elite clause is only for securing the kill with low difficulty test on the last hit against scenario boss because they often have high HP.

In 3~4 players encounter deck often loops so it going to deck instead of discard pile may not matter, or sometimes better or worse. Maybe you do want to draw this enemy again soon instead of other treacheries, just that the next time it comes alone and you can deal with it better.

So. If I understand the timing right (cf. rules#Skill_Test_Timing), at ST 3 you realise you're going to fail by one, so you use Book of Verse to get +1 (and later succeed by 0), you then resolve ST4 and ST5, and at ST6 you determine that you succeed by 0. You can then play Daring Maneuver to succeed by 2 instead (3 with Daring Maneuver level 2).

So Book of verse can transform one failure by 1 into a success by 2 or 3 per round, right ?