You are a little glass triangle stuck in a world of darkness, looking to make your way out.
In Tale of Prisso, you are trying to save lumenos in crystal caves full of darkness. Moving through this dangerous world, you will need to pick up glowing orbs that are dotted around. These are what you are after – and they also seem to have the added bonus of healing you should you crack your fragile body on the narrow walls all over the place.
As a glass triangle, the world is very harmful to you. Smashing into the walls of the cave, other pieces of glass, or hitting dangerous items will crack you and eventually destroy you. You can move your triangle by moving your finger around your screen, rotating the points of your triangle as well using both your hands. Moving your spikey bits will be key to getting through tunnels and around obstacles that you need to avoid.
If you start to feel you are too large, you can leave behind glass versions of yourself, making you much smaller. You can then break these old versions by tapping them, which makes their shards return to your body, increasing your size again. You also need to leave behind versions of yourself to reflect colored lasers where they need to go.
This world, despite being engulfed by darkness, will start to open up to colorful streams of light. You will need to direct this light to portals to make it further and further into the game. These puzzles are challenging and require quick thinking, but once you get the hang of how fragile you are and all of your abilities, you can start to make progress in returning the light.