S.T.A.L.K.E.R. launched with more than its fair share of bugs, but teams worked to patch the most critical errors as quickly as possible. The first patch squashed 68 bugs but rendered previous save games useless. Kinda defeats the purpose, doesn't it?
While they're at it, let's move to strike the periods from S.T.A.L.K.E.R.'s name. Boy is that a pain to type.