The objective of each mission in SNAFU TD is to prevent the enemy units from reaching the opposite side of the map. To accomplish this, you must build defenses using combinations of seven different towers that each have strengths and weaknesses. Once you build a tower, it will continuously search for enemy units to attack. The tower will attack it's target until it is destroyed or is out of range. The enemy will attack in waves containing multiple units at set intervals.
Starting a game:
After selecting a mission to play, you will have as much time as you want to build your initial defenses. During this time, towers are built instantly, and there is no penalty for selling towers. When your defenses are built to your liking, press the "Start" button to send the first wave of enemy units.