I was taken aback by this comment. The original Half Life engine has super tight and responsive movement, to the point where the average "tryhard" in a server would be executing all kinds of movement tricks that require frame-perfect inputs or very close to it. Watch some speedruns or HL:DS games and you can easily find examples of gameplay involving super precise movement. In CS there was a huge scene of movement based maps like surf_, bh_, and deathrun_.
Makes me think of something in the reviewers setup while playing Half-Life was introducing extra input latency and creating this feel of sloppiness.