It has plenty of potential to be expanded upon different levels with distinct building layouts and stuff.
The main complain I would point is that even if the enabled turrets activates their shoot animation when the enemy is in range, they wont do any damage to the mech unless they are pointed to a specific part like the railgun, which is clearly deceiving the player. Took me 4 attempts to realize that, and I honestly though that they were pretty much useless.
Overall it is a solid entry, good work.