Board Game Arena

I'm playing against someone in Ark Nova who takes their turns instantly after mine, there is zero delay, and they have an insanely high elo. It makes me suspect that they're cheating. Is that a thing? How would I tell?

There is currently only one game of AN you are playing, the opponent´s ELO (500+) is not "insanely high" but sure they is quite a good player.
I watched your game for a couple of minutes, you are right: their answer to your move came quite quickly. They has made up their decision how to play this situation - probably during your thinking time - and so there is no need to hesitate with their moves. It is like chess when a good player sees possible lines and patterns on the board and plays automatically as long as there are no surprising situations coming up.
In these few minutes watching I noticed that they began one of their moves three times and finally changed their first pick to a probably better one (I mean the association worker´s action project where the project was changed which made much more sense for me as well), this is a good hint that you played with a human!
I met this player a couple of weeks as well, it was a nice game where they took some time with their moves (mostly hours because of the time difference). They wrote a "gg" at the end and I hope to meet them again to get a re-match!

There is a long thread in the AN-section concerning bots (and smurfs), having read this I can´t see any reason to confirm your suspect.

Possible? Sure, most things are possible. Likely? I'd say no, given the complexity of the game and how much work it would be to program some kind of AI to understand all the various strategies and factors going on in a game of Ark Nova to outplay a human consistently.

Note that there's often the option to disable animations. While you are waiting for the end-of-turn animations to finish, the other player is already thinking and taking their turn. What looks like "instant" to you may not be so for the other player.

Notello wrote: ↑31 August 2026, 14:43 In these few minutes watching I noticed that they began one of their moves three times and finally changed their first pick to a probably better one (I mean the association worker´s action project where the project was changed which made much more sense for me as well), this is a good hint that you played with a human!

Nice catch. It's easy to overlook this when you're only searching for reasons to confirm your belief it's a bot, rather than all available information, even that which cuts against your belief.