Fun but difficult 2D city builder.
Kingdom has a fairly simple gameplay loop: you are a king or queen on horseback building a new kingdom from dirt with a few coins and some mercenary peasants, defend your kingdom from goblins, and expand! The graphics are 2D Atari-inspired pixel art used to fairly impressive effect with beautiful backdrops and a revolving day-to-night cycle.
In the day, you collect gold, recruit workers, outfit them with bows to make them hunters or hammers to make them builders. The hunters shoot animals for additional gold while the builders make defenses and expand your kingdom. At night you fend off attacks from goblins trying to destroy your kingdom and ultimately steal your crown, causing a game over.
This is where the difficulty comes in, you have a limited amount of time to gather resources and build up your fledgling city before waves of goblins come to tear your city down. Every few days a massive wave comes that tears your city a new one, which is when your crown is most at risk. This makes for tense and exciting games and multiple playthroughs while you hone your strategy and improve to progress further into the game.
Overall, this game has niche appeal, but it does what it does very well. A great game to play for short bursts.