Each level contains a field of colorful "electrons," slowly floating along a set trajectory. Your job is to start a reaction (the aforementioned "splodey circle") by clicking somewhere on the screen, then gently herding the electrons in the reaction before it expires, perpetuating the explosion of colors until you consume a set number of electrons. This means using the movement of your cursor, which repels electrons for most levels, to push them where you want them to go. Different colored electrons have special effects when they react, some good, some bad, which means you sometimes want to keep certain electrons away from your reactions. Also, while most levels require you to consume a certain number of electrons, others have different goals, such as consuming as few electrons as possible while setting a certain number of reactions.
The simple addition of being able to steer your electrons is a clever enough innovation on the Boomshine concept to make The Deep worth playing, but the developer seems to have realized all the possibilities in his idea and developed it into a great variety of gameplay. The different types of electrons and levels generate many ways to play with the core concept without ever feeling gimmicky or strained. The presentation is top-notch too: The graphics and animations are colorful and atmospheric without being distracting, and the ambient soundtrack really sets the mood, especially the joyful, ethereal theme that kicks in when you complete your goal. With its pretty production and well thought-out gameplay, The Deep is a clever twist on a familiar game that fully maximizes its potential.