On its face, Arnak is a worker placement game with deckbuilding and location expanding, kind of like a cross between Everdell and Dominion, but its secret sauce is that the game is SO short that you never have enough actions to do what you want to do. It forces you to get very VERY creative and very efficient with what you have and buy.
The game's even better in 2 player co-op with the The Missing Expedition expansion, which is a whole six chapter resettable campaign, highly recommend if you have a reliable 2-player group
Hot tips: Extra card draws mean extra actions so buy them whenever possible. The research track, while boring and small on the board, is actually the most important part of your final score. Slotting idol is extremely powerful.