New upgrades like additional starting money, or all towers built are automatically upgraded to a certain point would be nice. Also a power that turns a group of orcs against their friends would be appreciated.
To get as fast as a turtle all you have to do is...
put launchers all over the floor
put at least 6 proxy mines
put buzz saws as low as they can go on the left side of the screen
fill up the rest of the ceiling (the side that isnt above the saws) with turrets
and put 3 sentinels above the saws
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 "Zombie Trailer Park"){kind=icon}
 "Epic Combo!"){kind=icon}
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 "Screamin Beans"){kind=icon}