also I remember being freaked out because blood splatters would eventually shrink and vanish in pulses, so it looked the tatami mats in the first level were some kind of lovecraftian sponge.
this is a great intro movie. it's well crafted and evokes just the right mood. there was a few of these fuedal japan games that came out in the ps1-ps2 era that aspired to some kind of artistic integrity, in addition to being fun. the first tenchu was definitely one of them.