How to win level 12: If you haven't already, upgrade the drone tower to max level in the shop. Start lever twelve, and hit P (pause) immediately. Place 6 drone towers right where the road crosses. (Use the 1 key for fast placement or you will probably lose.) The wave meter is in the top left corner. Click the three waves that come after the first wave. Then, once done, click play.(Button is in middle top of screen.) Then once the waves spawn, keep your finger hovered over 1. Every time you gain 100 buildpoints place a drone tower along the road. (I usually put a total of 100-200) (Drone towers suck buildpoints from enemies). A few robots may break through or you may lose the first try, no biggie. Once all towers are placed, put a pile of magnets on the road. It may not let you at some places. The pile eternaly stops robots. Then build a bunch of rocket launchers by them. Add some rust towers to the fork in the road, and either watch your destruction take place or fast forward.
Easy win: Fully upgrade drones in the upgrade shop. In the maps start the level with all drones, they will keep sucking up building points, then keep building drone (I usually build 100-200 per map-seriously.) Then, once you have so much income you cant spend it fast enough, place like maybe 50-100 magnets on top of one another (find a place that has a glitch in it that makes it possible on that part of the map) Then, beside the magnets place 10-20 rocket launchers, and 10-20 rust. (the magnets make the bots stay, launchers hit all, and rust weakens their armor so rockets do more damage.) All the while your drones are hammering away at the bots. Rate up this comment to keep it alive please.
You should be able to sell the items for B-creds, for example: so and so worth 50 B-cred, sell for 1 B-cred. (one B-cred is around the equivalent of one penny). Rate up my comment if you like the idea, otherwise: Under rating threshold (show).