i played it through easy and normal. wasnt too hard but there were times of doubt. i ended the 50th lvl with 3 mazed out boss guns and a maze of maxed out peons and electric floors but only 4 rep
it was abit tough in the beginning untill you unlock the dragons. just throw 3 of them on and start digging. Those dragons pay for themselves in no time
a fun thing to do is get game over by one of the dropships and let the game keep running. I think i have around 60 people shooting at my body right now and more are on its way. The screen is filled
 "Now Boarding: Episode 1"){kind=icon}
 "Whiteboard Tower Defense"){kind=icon}
 "Color Infection"){kind=icon}
 "Ultimate Defense 2"){kind=icon}
 "intrusion"){kind=icon}