Ian Bogost is more successful in his subsequent effort ("Persuasive Games") in providing a useful outlook on analyzing and criticizing games. In Unit Operations, however, his arbitrary and by no means self-evident ontological assumptions (largely based on 20th-century postmodernism) muddy waters that could well be clear, and do a disservice to the craft of game design by making it out as though game developers are "bricoleurs," people making use of disparate odds and ends to put together something cohesive, which is a slap in the face to the concept of an "artistic vision."
Bogost does seem to believe one can work up to a cohesive vision through this bottom-up methodology, but this is, in my limited but still qualified practitioner's opinion, going about it the entire wrong way. Sure, a player or critic engages with a work from the direction opposite to that taken by the creator, which does reveal that this approach is useful to criticism, but to suggest that this it's inherent to the process of creation is either partially ignorant or dishonest, at least in a large enough number of cases.
This approach also discounts the value of the non-procedural aspects of media. How a mechanic plays out in when interacted with a videogame makes a difference for its interpretation, sure, but what in-game narrative elements, locations, presentation and side mechanics say about an instance of that mechanic's application are just as important, in fact even more important in some cases. These variables create the exact kind of top-down context that Bogost's method conveniently, and to its detriment, side-steps in its seemingly semi-ideological pursuit. For instance, a Jungian perspective to balance out his Lacan-informed method could have gone a long way in remedying this.
I should lastly acknowledge that Bogost's assumptions and philosophical foundations must surely have played a part in his later, to me more persuasive (pun unintended) efforts, but they didn't make the mistake of making claims like universality or generally applicable insight into the process of creation, which would entail that the assumptions were carried too far, as they do here. His method clearly works to an extent, but doubts definitely remain about his tendency to generalize without relevant information, his ontology and even his ideological motivations.