27 2 3Actions You only level up in Mercenary modeUnlock Mercenary by finishing the main storyKeep playing survival - forest over and over until you hit 40Achievement Walkthrough: Showing all 3 comments. Leave a comment. Just like billz says for level 40… use forest and stand near the 2 wooden boxes beside the cop car for the first 2 waves… buy the 7000$ mini gun beside you and start round 3… next buy the same 7000$ mini gun on your right and left… use the infinite ammo gun to save your cash… once you get to level 6/7 you should have about 30000$ and buy the flamethrower guns worth 10000$ for the 2 bottom guns repair any gun that looks damaged and the rest should level up 2/3 times every 10 wavesPosted by N30YRD on 13 Oct 22 at 15:38 I was getting around 4 to 5 levels playing 'Economic' mode. Same strategy as Bill and N30YRD, but don't try to get to $150,000 cash. Just play till wave 10, the final wave.Posted by The Hot Glue on 04 Jul 23 at 17:18 Its worth noting the achievement doesn't pop during the match. So as soon as you hit 40 just die on purpose and the achievement will unlock on the results screen.Posted by Reelbiggerfish on 14 Sep 24 at 15:27 Leave a comment