A tower defense style of game. Click on a tower from the list on screen to build one, and click on an already built tower and you can view its stats as well as the upgrade options available for it. Different towers are good for different things - arrow towers are cheap and offer low damage but boast a very high rate of fire, and are able to target both land and air. Cannon towers are rather slow to fire shots off, but the shots deal a high amount of damage as well as causing splash damage to things nearby, though they can only target land. Air towers deal good damage with a good rate of fire as well as range - though they can only target the air. There's elemental towers as well - water towers can deal medium damage with a high rate of fire, are able to target air and land, and can be upgraded to deal splash damage. Earth towers deal huge amounts of damage, but they offer a slow rate of fire and can only target land. Fire towers deal large amounts of damage and fire slowly, but deal splash damage as well as targeting both land and air. There's also the combo tower, also known as the rocket - it deals fire, earth and water damage, with huge range and high amounts of damage and can target both land and air. Not all towers are available to start - early on you'll just have the basic towers. To get the others unlocked, you'll need to perform research. Research costs resources though, which you'll need to balance carefully. This is a challenging game, but it's deeply satisfying and tons of fun to play, making it a top notch title!