Adam Saltsman and Robin Arnott have made their previously Venus Patrol-exclusive, suffocating sim Capsule available for sale this week for Windows and Mac. According to Adam's blog post, Capsule takes about 2 hours to complete and is described as "technically a survival-horror game, featuring a posthumous epistolary narrative and a reactively generated abstract landscape that is different every time you explore, and tailored to deliberately create tense scenarios and close calls."

Close calls for me involved running out of air quickly, much too quickly to make a dent in the 2-hour time requirement. Those better at resource allocation and claustrophobic situations can purchase Capsule for $8 using the Humble widget.