But there are definitely entire weeks (or weekends these days) of video that aren't all that useful unless you're trying to build exactly what Casey is trying to build.
https://hero.handmade.network/episodes is a must if you want to cut some corners on what you watch.
Off the top of my head, here's my suggestions:
* Weeks 1-15 are all useful - it's really a great introduction and kool-aid provisioning system
* Week 20 and 21 has some introductory lighting stuff.
* Week 23 and 24 has some good performance profiling stuff.
* Week 25 and 26 has some multithreading job queue stuff.
* Week 28 and 29 has SIMD/SSE sound mixing implementation
* Weeks 36-38 has debug/performance infrastructure
* Day 235 and weeks 48 and 49 are the start of OpenGL initialization.
* Week 74 discusses particle systems
* Weekend 3 discusses compression
* Weekends 6-14 are the core software-renderer-to-OpenGL days
* Weekend 23 is a re-implementation of lighting
The other stuff is exploration of concepts that are either specific to Handmade Hero, or are much deeper implementation detail type stuff - not entirely necessary if you're skimming.