In Solar Defense, the aim of the game is to defend your station for as long as possible by taking down as many enemies as you can as quickly as possible before you become overwhelmed. You start out with an empty space station about to be attacked and from then on its a frantic race to build weapons, shields and various support structures like reactors and engineering bays to allow your station to survive under the onslaught.

Despite the simplicity of the gameplay there is quite a lot of complexity lurking underneath that will leave you itching to have just one more go to tweak your base design and see if you can push your score higher. For example, each base component can be upgraded multiple ways and you have to plan your upgrade path from the start having to make tough decisions like; "Can I fit another cannon on if I do these shield upgrades instead". Upgrades are nicely balanced and there is no one way to succeed, its up to the player to discover their preferred play style.

While the trial demo version is limited to 30 waves and level 10 technology, the full version allows you to play on until your base finally becomes overwhelmed. The full version also adds a number of powerful unlockable weapons and 3 different defense scenarios that require the player to adapt their defense strategy accordingly. Individual games play out in under an hour and the player may save and quit at anytime and resume the action from the start of the last wave.