Sometimes when i enter the corruption i am unable to do anything other than turn on/off auto attack... that's quite annoying as it wastes an entry and it forces me to refresh and miss out on the corruption for that half hour
from bottom to top: machine gun, saw, lightning, saw, saw on both sides, upgrade bottom to top priority, update both sides kind of evenly and you'll easily beat every level, you dont need upgrades in the heavy artilery obviously (or in machine gun even) choose all the most expensive upgrade options
Glad it felt like a nice, condensed experience. Expect new games from me soon!