this is the dumbest key setup ever. It won't let you do a duplicate, then you have to only put one key in at a time... which is bad if you wanted to change a key.
build only the cheap turrent... and always get another elevator. Then only upgrade to lasers in one elevator at a time. (you have to sell the cheap turrent.) If you only have one, you may have to move it around.
 "Stellar Squad")
 "Super Duck Punch!")
 "Sentry Knight Conquest")
 "Obliterate Everything 2")
 "Crush the Castle Players Pack")
 "The Next Floor")
 "Starcom")
 "Endless Zombie Rampage 2")
 "Bunny Invasion 2"){kind=icon}