He got some great shots in that but his BHing isnt anything unusual.
Anyone that played a long time ago could BH like that by using the mwheel without any script.
If you're impressed with that you should've seen some of the things that Sev used to do.
He'd build up so much speed he'd be able to do ski jumps on as_tundra.
Or, in TFC, he'd go faster than Scouts while BHing as HWGuy.
He always used a crazy high sensitivity anyways (little higher than this guy phoon's), so that helped a lot to gain more speed.
This is why airaccelerate was changed and enforced in competitions and also why the little slowdown after you jump was implemented into CS because BHing, as fun as it was, ruined the game.
Pretty funny how the player's he's going against don't seem to have any clue how to combat it though and don't seem to use any sound whatseover since he is making noise when he's doing that..