New one on myself as well, really appreciate the heads-up on it.
Impressive as the footage is, i think you simply have to take into accont it is nothing but a TECH DEMO, so even IF it's running on standard PS2 hardware, rather than high end PC from that era, the game engine is doing little more than animating pre-set routines, designed to showcase ideas team would of liked to put into the actual game and show off various special effects their engine could handle.
Taking an impressive game engine and turning it into a fully fledged game is not mean feat.
Rebellion's PS3/360?PC AVP game Engine looked very impressive when i 1st saw it running, actual game however was massive let down, A.I on the Xeno's in particular.
Then of course we had Aliens:Colonial Marines early footage, compare to actual game released...
Still not wishing to take anything away from this superb find.
Chalk up yet another Aliens game that could of been....