A cheese/exploit base is using an unintended flaw in the AI programming to basically have a free ride.
EG: When zombies could not dig down, building a base underground was an exploit; You'd just have to go a few blocks down and place a block over your head, and you became untouchable by zombie hands. Put iron bars there and you can shoot them as they gather collectively and unthreateningly above your head.
EG2: Previously in A16, A17, A18 zombies would attempt to walk on steep block shapes; But they actually could not walk on them at that time, so instead of walking on it, they'd just slide and fall down. This was exploited to make loop bases in which the zombies
THINK they can reach the player, There's a block path there after all; But in actuality the zombies cannot reach the player, ever. They just try, slide down the wedge tip, and then have to walk around to the staircase and try again.
EG3: A few alphas ago, Zombies would blithely walk rig...
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