Very addictive.
I suspect that despite their cute animations that evoke randomness when you play a square bonus, our friendly vampires always "randomly" give us the valid 2x2 that contains the most uncovered cards.
If I'm correct, we can sometimes cheat back at them when they suspiciously don't give us the maximum number of cards.

2?4
9??
3??

In the example, if the given square is top right, I think we can directly stab the ? between the 2 and the 4.
This makes the gains of the square/hints/get what you can/pass strategy even better.
Please tell me if you encounter a situation when that was not the case, I may just have been lucky the few times the situation presented itself.

EDIT : just lost against last vampire but I gained huge knowledge from it :

Let's talk about N+ cards : they go from 2+ up to 9+ , yet you never see two identical hint card on the board. This clues that the eight plus hints are set on the cards at deal time, a different one on each un-flipped card. Let's say for example that the first uncovered card is a 7, where do the hints 7+ 8+ and 9+ go ?
They have to go in some unknown order on the 8,9 and vampire cards.
1st conclusion: every +hint that has a number lower than the first un-flipped card is safe.
2nd conclusion: assuming +hints are placed fairly, the nearer from the 1st flipped card the hint is, the safest it is...
Using this proved helpful with the first vampires that seem to play fair with the +hint cards, but proved disastrously deadly against the last one : I picked 4 times the plus sign equal to first flipped card, that is supposedly the safest non 0 risk, and found the vampire card each time, including on a +2 card...
Now is time cheat back at him, since he likes to pick the lowest possible hint value for his card, against him, a hint equal to first flipped means stab time, and any other value means safe card.
I'll show you who cheats best...

Hey @setafult, very nice speedrun. Almost no hesitation, and I think a single time where you used a useless > when a potentially useful + was available. The only significant time saving you could have gotten is to better follow your blood count and skip rounds once you have enough to still be over 5000 at the end of the set.
Another way that would completely change the run strategy would be to build a tool you'd feed the first few rounds of cards and hints into, and it would find from that the current random seed and predict where you should stab next. (like the tool for the battleship minigame in zelda wind waker). Such a tool might kill the fun of the run so maybe it's a bad idea.

the trouble is that it is now the year 2024

@RealShadowCaster thanks! Your idea about a "seed finder" tool is interesting, I'm sure somebody out there could do it. But yeah, some people might not find it very fun, so if someone did we'd probably have to make separate run categories. Also your idea about the 2x2 grid picking the bigger area is definitely correct, that's one of the tricks I used during the run all of the time.

Dang, your points about the n+ tokens are interesting. I was abusing some of that behavior in my runs, but I think your analysis is a bit more thorough and can lead to some better strategies. I'd be interested to see someone implement that in a run.

Oh yeah, n+ tokens don't work the same at all with the last vampire, because he's actually hard-coded to cheat. Thankfully, he cheats in a predictable manner, so in the last stage you actually have a way better trick up your sleeve, though honestly it's been a while so I don't remember exactly what it was. But if I remember correctly, if the n+ token was the same number as any card you have flipped over, it was guaranteed to be the vampire card. Or maybe it was just if it was the same number as the first card. You'd have to test it.

EDIT: You can see me use that trick here: https://youtu.be/7VtRCHrE9G4?si=e0ARD7z0iGrE0ZlI&t=333

This is really fun, but also I'm terrible at it.

Great game! I really love all the details with the changing card backs. This has so much character and interest. One of my favorite Pico 8 games!

Bro this is so addicting. It goes to show how fun the core loop is that there's no more content but I keep playing and running up my streak cuz it's just so fun to do.

This is really fun now that I know how to play. Good job!

playing safe was never an option

I can't trust anything in this game, I will be just fine then the most unlikely thing happens then the next round it happens again.

I found a bug with the game saving, If you close or refresh the page while in the game, It may not save how much blood you actually have, and give you less blood. I find it mildly annoying and probably not very high on your list of things to fix. If you could, that would be great.

Amazing game! It is very fun and addictive. I wish it didn't end at a certain score. I really wish the story continued. But, even if it doesn't, it would be cool to be able to keep playing for more and more blood. The high score mode doesn't seem as fun.