Koya Rift is an action-packed platform shooter that is built around circular, adaptive gameplay that emphasizes replay value by challenging the player with procedural content tuned to their skill level. In Koya Rift, the player must enter a hostile planet and destroy an alien race so the planet can be colonized. Each game, the player is dropped off at the surface and must venture into procedurally generated caves, earning upgrades and buying units as he goes along. The difficulty adjusts precisely to the skill of the player over time, providing them with a consistent challenge. The goal of the game is to provide a challenging, yet casual experience that’s easy to pick up and put down. A game of Koya Rift is pretty straightforward – you find yourself above ground standing in front of one of the delivery pods from the mercenary mothership. Your minimap hides the area below ground – and you have no idea what awaits you. The terrain of each level is procedurally generated (meaning it uses advanced algorithms to make itself different every time, providing nearly endless possibilities). Below ground lies a web of tunnels and caverns that is different every single time you play. It’s impossible to know what awaits you behind every corner. Procedural generation isn't just in the level – all of your enemies will seem different too. Their size, speed, color, health, damage, and weapon behavior will be unique for each one you fight. Your own weapons are generated the same way – the Lances you bring along with you to levels are generated out of endless possibilities. One gun may fire large, single shot energy blasts that slow down and weaken all enemies in a large radius, where another gun will shoot bursts of many bullets that curve in every direction with a waving motion, another gun that fires several shots at once but can pierce through walls and home after enemies, and another that heals and enhances your allies. You have to venture down into the unfamiliar cave system and eliminate all of the Phantom Crystals (Where the enemy soldiers are grown). Unfortunately the Phantoms are hunting you the whole time, while their crystals evolve and grow. If you manage to destroy all the enemy crystals, you win the level. Don’t get too proud though – if you beat it too easily the game will know and will be sure to adjust the difficulty for next time. Game difficulty in Koya Rift is complex – it’s not a simple modification to the amount of health you have, and it isn't a simple easy-normal-hard scale. Difficulty is a very precise unit of measurement that expands near-infinitely in either direction in this game. If you beat your last couple of levels easily it will slightly increase, if you keep getting beaten down without a fight it will decrease to help you out. Difficulty adjustments affect almost everything in game – from the reaction speed of the Phantoms, to the speed at which they grow and evolve, to the cost of your allies, the experience they need to level up, the accuracy, size, fire rate, and density of your energy weapons, the rate of health recovery, the effects of special weapons, the size of the levels you play on, the health and damage of your enemies, the speed and fragility of your allies, the cash value of killing an opponent, the swiftness and force of enemy attacks, and even more. There are so many values that change, and when they do change, they change with such subtlety that you will not be able to pick out exactly why this next game seems like more of a challenge for you than last, or why you’re finally able to beat that one level that you were stuck on for so long. These items combine to create an excellent formula for expandable gameplay – in the end you have a game that you can always come back to and find something different, and always be challenged regardless of your ability.