Attack Speed Edit
Attack speed determines how fast the tower can attack. It's default value without Laboratory starting upgrades and manual upgrades is 1.0 which means it shoots once per second. Each upgrade makes it .05 faster.
You unlock this upgrade at the very start of the game.
Extra information Edit
- You can upgrade up to 180 times, making than, upgrading at max, you can shoot up to 10 missiles per second.