I beat twice now got the same ending. I mined a lot and took out a few contracts the 2nd time. First time I was more contract based but still mined bunch. Does not seem like I caught echonic. I wonder what I would have to do to obtain an alternate ending.
I beat lv.6! I used lv.1 turtles for a while, like 5-10 minutes until both sides could be fully saturated with lv.1 turtles. Then, I used version 2 turtles for 2 minutes, version 3, and so forth to lv.5. Then for another 10 minutes I used lv.5 turtles until I could get about 80% of the way. Then, when I had $60k I made 20 of the version one last unit. Worked amazingly, I didn't lose any of my planes and as I got more money I built another 10 or so and won. All from the side that the turtles were advancing slightly further from.
Lv.6 might just be beatable, I managed to get 3/5 of the last unit fully upgrade version 5 past. Would take a lot of patience to grind up enough money to get 30-35 of these to win.
Turtles are making money in mission 6, but I can't get even lv.5 razzos through. I think I have to wait until I get more money and send more powerful units.
Beat lv.5 with turtles + version 5 razzos. Seems like you need a money maker either bugs or turtles and then a finisher. In general you want the money maker to be version 1 since its the best bang for your buck. The finishers you want to be as powerful as possible, so the enemy gets no money for killing them. Thus version 5 razzos.
Roadsters work great for lv.3. Seems fast ground units are the way to go, version one. The idea is you are gaining so much money per tile that you can quickly crank out more and more units. Meanwhile the A.I. quickly becomes overwhelmed.
As for the people stating turtles always win, doesn't work on first stage, you only get $2 money per tile, and then $50 or so when it gets through. I spent $200 on a turtle and only got 100 back.
I noticed that I cannot build the tower of water until I build the tower of light. I've also noticed the game seem impossible if you do not build a tower of light.
 "Knightmare Tower"){kind=icon}
 "Idle Hacking"){kind=icon}
 "OutHack"){kind=icon}
 "Anti-TD"){kind=icon}
 "BowMaster"){kind=icon}
 "Stop the Darkness"){kind=icon}