The evil Megagate erased the formulas in your book of magic potions. To recover them, you have to destroy him and his followers. Learn to use your magical powers to reach him and complete your mission. You have 3 kind of magical powers, that you can use in different ways: a comprehensive tutorial will show you step by step how to progress when you play for the first time.
Arrow keys A/D to move; E/Q to switch weapons; space bar to see the map. Use the C, V and X keys to show controls, achievements and skills respectively. Move the mouse to aim, press the left mouse button to give power to the ray and release it to shoot. If you use fire or the necro-hand, simply click to shoot. Use the ESC key to open the menu. You cannot jump or fly directly, but if you shoot to the ground you'll be launched up. If you need a jetpack, use the fire mode and shoot down. Every time you use one of the 3 magical powers, their respective force will slow down; to recover it, switch to other mode (a vertical bar near each icon shows how much power is available currently at the corresponding mode).