While Firewatch graphics look good, Firewatch uses the Unity graphics engine with fairly simple textures. This makes it much more likely to run on low end PCs. An Nvidia GTS 450 graphics card is the minimum Firewatch requirement, whereas it will likely need a fair amount of system memory to run smoothly, 6GB has been quoted as minimum RAM requirement.
Firewatch is a mystery set in the Wyoming wilderness, where your only emotional lifeline is the person on the other end of a handheld radio. It’s your job to look for smoke and keep the wilderness safe. An especially hot, dry summer has everyone on edge.