Each set-piece, whether you're duking it out in a narrow corridor or caning it across a wide expanse with a gunship in hot pursuit, feels like Valve sat down on every single occasion and asked themselves "is this fun?" There's barely a single moment in the entire game where you'll feel bored, unchallenged or maddeningly overstreched. It's pitched perfect right the way through, always testing you - sometimes to the limit - but never stacking things up so as to feel unfair or outside of you capabilities.
It's also important to stress that Episode Two does introduce new enemies, hugely varied environments and, eventually, new gameplay elements when the time is right - and all feel in-keeping with what you'd expect from Valve. First up, you'll encounter the projectile-vomiting Acid Antlions, which come armed with a devastatingly accurate attack that keeps you pinned down, desperately waiting for the right moment to poke out and return a few well-placed grenades.