4A Games has moved to quell rumours that the new engine that powers its debut title, Metro 2033, is derived from the X-Ray tech found in GSC's PC title, S.T.A.L.K.E.R.
Asked about the connection between the engines during an interview with Digital Foundry, 4A CTO Oles Shishkovtsov said, "There's no relationship. Back when I was working as Lead Programmer and Technology Architect on S.T.A.L.K.E.R. it became clearly apparent that many architectural decisions put into S.T.A.L.K.E.R. engine were great for the time when it was designed, but they just doesn't scale to the present day.