I found it frustrating and annoying. Hey, look the core popped up a "1" again. So all those echo bonuses you've been building? Yeah, they're useless, because you're going to clear this one immediately.

That single RNG aspect, and the fact that more "difficult" opponents simply mean that they pop up a "1" more frequently, torpedoed the entire game.

The math itself isn't hard. There was a nice bit of tactics to figuring out how to set and maintain your echo bonuses without clearing the entire board too quickly. I appreciated that.

But having the RNG be able to just burn through your turns, and giving you no recourse to stop it, completely ruined the game.