Rough legacy whiteboarding process. Valve unfortunately is using whiteboard interviews. Something that fortunately most companies have abandoned. Whiteboarding, while great for fresh out of college comp sci students, is not something I learned to do as I have been in the industry for 20 years now. I worked through the problem, but overall had a really difficult time having a zero feedback loop environment and occasional scoffs from the interviewers. The entire process was extremely demoralizing and wasted their time and mine without getting to actually show any of my strengths. It's unfortunate that a candidate who's employers have included NASA, Sony, and other Fortune 500's isn't able to share my experience with them. But I think they are looking for a younger crowd. If you want to pass this interview, brush up a lot on your whiteboarding, communication and coding. Advice to Valve: Please try out take home assignments. You are severely limiting your talent pool otherwise.