Solid game, difficult at first, here's what worked for me:
1) Never reload your own weapon, always have an assistant. Fire until empty then switch weapons.
2) Only have 1 in search party, first focus is keep going unnoticed as low as possible, followed by survival as high as possible.
3) Put everyone else into shooting, swap out survivors for shooting of 3 when you max it out, place all others into melee.
4) Equip 1st weapon as Springfield once acquired, followed by Remington once acquired.
5) Equip second weapon as MP5 once acquired, followed by M4 once acquired.
6) When shooting, Remington can 1 shot kill most zombies excluding fatso and fast purple lady. Aim for 1 shot kill zombies first, purple ladies when they get close.
7) When you switch to automatic weapon, target fatso and purple ladies that get too close, switch back to Remington as soon as it's reloaded.
8) In later levels use remote mines in the center of the hoard early in the stage to thin out the numbers.
I had 2 issues in my game play. 1 - 2 keyboard controls at the same time did not work well. If holding say the right arrow key and then jumped, right would stop responding. 2 - When powered up as the blue moth thing, instincts implied I should press down to stomp, but did not.
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