Got to one bit now (level 9?) that makes the game lag like crazy (too much going on in the level, I suspect). And they expect me to perform some kind of amazing feat of dexterity with my mouse whilst playing at like 5 FPS
Suffice to say, I'll wait for Portal 2
If anyone is considering Prelude, let me just say: this game is about reactions and manual dexterity, not problem solving. It's not traditional Portal at all.
Indeed, don't have a clue how to get past lvl8 (i think) where you have the multi levelled area with falling ceilings and bots. I mean i can see how its done, just not with the bots raping you immediately.