I've played the demo and it looks thoroughly cool. There have been some minor tweaks to the gameplay that make it even more fun, such as being able to carry up to 4 weapons rather than 2. This little change allows to play with all the cool new toys like laser cannons and old favourites like rocket launchers without having to worry about ditching a weapon with full ammo that you might want/need later.
Unfortunately we've all learnt that oftimes what you see in a demo, and what you actually get at the end are wildly different things. The R500 price point (R480+ might as well be R500) also makes it a throughly unattractive buy without more playtesting than a 20-30 minute demo
It's truly a pity because the original F.E.A.R. was one of the few FPS games that I actually ended up buying after playing it through first - it was that good.