The machine gun turret would fire 3 consecutive bullets intead of a long laser blast that a laser turret would. The turret would cost 10p to balance the turret's power. It can fire up to 3 bursts of 3 bullets, or 9 bullets, before cooling down for 3 seconds. It is capable of firing in 2 directions at a time and has a slight delay between aiming. It can only fire in cardinal directions and each bullet would do 3hp of damage (up to 9hp of damage per burst) The unlock level would be 5 due to the power of it.

Top view: http://imgur.com/Nnz5p14