Its been a while since I used GameGuru so apologies for not being up to speed.
When I last had a go there was a serious lack of support for lights e.g. static lightmap quality was not very good, especially when trying to produce decent looking shadows. Range and brightness didn't have enough control and you couldn't mix static lightmaps with dynamic lights, it was one or the other.
Also it was only possible to cast dynamic shadows from the sun and neither static or dynamic lights cast dynamic shadows which made indoor environments look very poor compared with the outdoor demos.
Finally it was not possible to give enemies waypoints that could navigate up stairs so gameplay only worked on a single level which is very limiting. I had a quick play of the indoor example maps and the zombies still have very bad pathfinding in more complex geometry.
I'm really pleased to see the Steam release is going well and the product has improved in many ways since the good old BETA days of Reloaded. However these issues have been there since this time and I don't want to invest a lot of time until there is a proper lighting solution in place.
The gameplay for enemies with weapons is actually quite good but having all of this great scenery when they can essentially only navigate the terrain properly is a significant drawback.
If these issues are not planned to be fixed soon I think that is quite disappointing. We have moved onto to things like 3rd person without ensuring the basic architecture of the engine is implemented properly first.
Edit - This is not a bash GameGuru thread. I've been a GOLD pledge since the beginning and would just like to see more of the fundamentals being addressed.
Windows 7 Pro 64bit, Intel i7 3.4 GHz, 16GB DDR3, NVIDIA GTX 760 2GB DDR5