GLASS x CANNON is a risky top down shooter roguelike. You are always very low health so you'll have to dodge and use blood to survive, collecting items and getting stronger to defeat a powers, crossing into our world.
Each room you have one hit to survive, but clearing room restores you. Some items give you more hits survive, but you are always risking and have to be focused.
Each run you'll collect Srystals, you can use them to unlock new items, special items, etc. Playing with additional challenges will give you more Srystals, so it's a great reason to check your skills.
To beat final boss you'll have to go through more difficult alternative path, collecting The hummer and breaking Mirror with it, collecting a Heart of Deadless that will allow you to survive Sapphire Flame's last attack