Halo Infinite's campaign co-op is now available for preview testing for insiders - and we've had the chance to give it a thorough testing. How does it work? What are the limitations for co-op play in an open world? How does person-to-person latency work out? And crucially... can you run Halo Infinite on Steam Deck and how well does it play? You've got questions and Alex Battaglia has some answers.