The envisionment of TK is to bring you what was promised by GSC for STALKER: Shadow of Chernobyl, instead of the gutted retail release we were left with. TK aims to cover every aspect imaginable from gameplay intended to genuinely scare the player, to graphics for the absolute best visual experience, cut mutants, absolute realism, optimisations, stability, and a complete game mechanics overhaul, all without breaking the story. The idea is to present the player with a complete retail experience for the purist that liked SoC but wished it was far more fleshed out. In no way what so ever does TK try to be like old beta or alpha builds of SoC, TK aims to enhance everything SoC already has - nothing more, nothing less.
This is something that can't be fully appreciated in a image or even in a video but what can be seen is that different kinds of lighting on certain surfaces will result in a reflection of sorts being generated, upgrading X-Ray just that little bit more ;)