Bronerog (Boss)

The achievements are getting a touch harder now - save 180 prime and without upgrading any towers. To aid you sell any towers which are not in range of the final enemies towards the end of the level.

The boss is not so tough actually especially against high level mortar towers.

Here is my layout which pretty much killed the level with no problems. Make sure you destroy all the totems for extra prime, and of course utilise the anomalies.