Hello achievement hunters,
I recorded all the missions so you can see where you can find Booster Shots or on which points it could get difficult. if you are playing with 2 people, I recommend a player with normal guns (Assualt Rifle and a Pistol) and another one with a Rocket Launcher to take out the big guys fast. The third person could be a player equipped with a Sniper Rifle, although we played with another Rocket Launcher (starting from the third mission). Once you've ran through the whole course, your achievement will pop.
Special thanks to POLAK fr06 for joining me.
ENJOY!
Edit: GesterX shared the following: "It should be noted that you need to complete the entire mission from the start for the achievement to pop. Last night I got matchmade into a game which was about 2 minutes into the mission and did not get the achievement at the end." That said, be sure to start each mission from the start.
Edit 2: KP ScuzzyBunny has confirmed that you can play up to level 15 without a uPlay passport. Afterwards, you will need to buy it. Additionally, you can play all the co-op missions on the 'Casual'-difficulty setting. This will not give you a lot of EXP and you can still finish all the missions while doing so. If you are past level 15, you can still try to find a local partner to finish the co-op missions that way.