Solar Flare is a fast-paced real-time strategy title with different planets battling each other while orbiting a destabilizing sun. The aim is to destroy all other planets before the sun explodes. At the start of a game, where the player can define the parameters such as the number of opponents and the difficulty level, the different planets are placed on different trajectories around the sun. All planets move around automatically at different speeds (depending on the distance to the sun).
Each planet has two important parameters: health and energy. Health represents the general state of the planet (too many hits cause the core to rupture) while energy, which re-fills gradually, is used to perform actions. Movement actions include rotating the planet or warp to move the planet along its orbital path at a faster speed, mainly used to chase another planet or to get out of a dangerous situation. Energy can be spent on three types of structures: plasma cannons, energy shields and power plants. These can be placed on any part of the surface, but the position determines its usefulness. Cannons are use to attack other planets, shields intercept incoming projectiles and plants provide additional energy.
Each of the three types of constructions can be upgraded. For a cannon this includes a cluster upgrade, causing fired projectiles to explode into clusters and damaging more areas, and a damage upgrade. For shields both a deflection and an absorption upgrade is offered. Plants can have an energy and a recharge upgrade. Constructions can also be sold in difficult situations to receive more energy quickly.
The mouse is used to rotate the camera, zoom, and target areas on another planet to attack. Fired projectiles move towards the assigned goal regardless of the orbiting speed, so the movement path needs to be calculated when aiming. When multiple cannons are present, they can be fired at once, but need some time to recharge.
A few random factors are introduced through asteroid scattered around the orbital paths. Energy asteroids provide additional energy when shot, health asteroids repair the planet surface and restore health, black hole asteroids spawn a powerful black hole that sucks in incoming projectiles and deadly asteroids act as bombs that explode when shot. Next to the singleplayer, skirmish sessions, the game also offers multiplayer through LAN.