Board Game Arena

Does it employ a new mechanic? Or is there a game you'd compare it to and it does the thing that game does better?

The game mechanic by which resources are spent and locations are raised is not one I have seen in other games.

Also, for a small deck game, the difficulty is fairly high. I wouldn't say the complexity is super high, but the difficulty seems to be.

I'm not sure I would describe this game as an engine-builder.