I really like the HQ rules so far, though I have questions. One comment I would make, though, is that the mechanics sort of outsource simulation to the narrator. If a player finds a luger with a full magazine and wants to shoot enemies, it's up to the GM to know how many shots he can take. It's up to the GM to know if an archer's attempt to shoot an arrow 400 m straight up passes a credibility test, or how nasty it is to be hit with a billiard ball dropped from five stories, etc. In simulationist games such things are often baked into the rules or into tables of stats. To decide how tough or impossible something is, I need to know or look it up myself. This is not a bad thing in today's search engine enabled environment.
I often ignored those sorts of stats, but having them as a backup was nice.