This specific minor version of 6.9 is really strange because it is the least balanced, most difficult version of poker defense in a very long time. Hopefully future versions will be more balanced.
Terran Bio seems to be the most consistent here. Marines are the main focus and they aren't too difficult to get. There are two levels in particular that are extremely difficult: Lings (around lvl 50) and Mutas (around lvl 60). These levels are near impossible if you have only explosive damage types.
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