40 day survival in normal: get 1 gunman, save up for shotgun, get some more gunman and 1 repairman, get up to around 30 gunman and upgrade wall once, get up to 60 gunman and then buy 2 missiles and 1 shield, buy "Old Glory" and max towers, then max "OG" reload, then max "OG" ammo... max out the wall and you have just relax and shoot tanks
I've introduced counters to some more achievements (not all of them yet)