Anyone who is struggling with 'Wet work' should just do it early. I did it in the 1st month (4th mission). There were quite a few aliens, but they were all sectoids.
All I did was kill the mind merging ones to cut the numbers down quick. Just remember to rank your soldiers up with this achievement in mind (sniper should have snap shot for example) and to keep moving forward before shooting (even if this leaves you flanked, the sectoids at the back usually mind merge with the ones on the front line, so just move forward and kill the back ones. The ones flanking you will end up dead anyway).
Also don't be afraid to use your grenades.
Done with the basic squad size/weapons/armour with grenades.
Last edited by PhilAvery; 01-04-2013 at 02:29 PM.