Tiny Troopers 2: Special Ops

The achievement says that you must hold 3,000,000 CP at one time, not cumulative. Depending on if you bought the Double Command Points perk in the store, this might take you a while. By completing missions and surviving in the zombie maps, you earn CP. You earn more CP by completing the secondary objectives in missions. Repeating missions that you are comfortable with makes it go faster.

I personally found Operation 3 Mission 7 (Sandbox) was the best method for this. I added a Rocket trooper, started the mission, and then bought the intel right at the beginning. Theres no real method to the madness, but since you have 5 minutes to destroy every fighter I just went straight to the first fighter, destroyed it, opened my map and hit the collectibles on the way to the next one. I went from 830,000 to 1,120,000 in 6 minutes. I left a lot of opportunity behind (Some buildings and roaming troopers), but just wanted to leave after the last fighter to get the outfit bonus and start the next run. Just hit and dont get hit. There is a roaming tank to use your rocket on and a roaming vehicle as well to use a rocket on so you have 1 spare rocket to fire at will (There is a bunker of troopers, but i avoided it in my run just because of the path i took which was a clockwise movement starting at 6 o'clock then moving to 9,12, and 3 respectively. I had a 4x multiplier the whole run.