To beat hard is to start on easy and get 4 powerful characters, and two powerful weapons(the best) the atomic bomb and the hell breaker. Then restart the game while having the same weapons, just max out the mana generator, the haste, the more damage, and the tornado. You will go breeze through all the levels.
 "Bug War Recolonize"){kind=icon}
 "Warp Game"){kind=icon}
 "My Little Army"){kind=icon}
 "Epic Combo!"){kind=icon}
 "Sentinels: First Wave Beta2"){kind=icon}