I played and I am disappointed after the destruction of the eye play a mother ship is still pending and does not include the coin (not reckoned me) take this correct as you can
the game can be complete, but you need to skillfully play, for starters invest in a "shield" and "generators" by setting them at three places, in this way, all buildings will have 2x stronger power (on both sides), then invest in buildings for ammunition (five buildings is a maximum, in the calculation of 4 machine gun and 1 flak gun), they serve as both batteries and warehouses, you should also buy a "damage control building" and "synthesizer", completing the construction of leave free outskirts of the city to build there, "decodder" and "jammer "building them on obrzerzach give them 85% more chance of surviving the harshest waves until the final boss.
the difficulty the mother ship is a massive releasing small scout ships .. shield will not stop them, as well as basic rockets derived from energy - is not the best in the "machine gun" can only build these buildings but if you want you can build a "flak gun" and four machine gun, as I wrote above, I "flak gun" serves only to destroy the eye of the ship in the moments when it is reversed, the whole Rasht is a skilful energy management