If this game, based on your body's constant fight against attack, is really the 'all action, accurate real-time simulation' that it claims to be, you have better get to a doctor pretty fast.
You take the part of the body's defences and trundle along the blood stream shooting at the nasties with a kind of medical laser. Whatever happened to good old antibodies? You are provided with a map of the blood system and what can only be described as rudimentary steering. You carry on along an artery unless you wander too close to the walls near a junction. Then you get whisked away into the side passage by the rush of blood.
The game is abysmally slow and the graphics poor - consisting mainly of lots of red circles. Despite the ad's claim to full colour graphics, this mostly comprises just two hues. Presumably all this is supposed to give you the feeling that you're watching a re-make of 'Fantastic Voyage'. The total absence of Raquel Welch on screen leaves me unconvinced.
The bacteria that you are to defend your body against are a horrifying species I have not met before. They look for all the world like flickering yellow blobs - very dangerous and liable to bring on a severe case of sleeping sickness within minutes.
Unless you have a vampirical obsession with blood, this game is unlikely to appeal for longer than the opening screens. Not recommended.