Some deadly crystals, probably some form of aliens are threatening to take over the planet earth and now the only hope for the earth is the plants. This unique defense-style battle game will need the player to place the plants in tactical positions to attack the crystals and earn cash that can be used for availing more units and upgrades. As the levels increase, more elements get introduced into the game play making it slightly more challenging but more interesting nevertheless. The game offers tips that come handy while playing the game. Use the mouse to control the game play. Symbiosis is one of our many Strategy Games that we publish on TheGamerStop.com. This game is also tagged as a Strategy War game. Click the play button to start having fun. To play even more free games, view our popular and new games page. If you want to play more games like this, then you can simply check out the games inside the game tags that are the most relevant to your interests or the Strategy Games category or the games like this game page at the end of the game tags.