Nicolae Andrei from in2gpu.com says:
"It has been a little more than a year since Metro: Last Light came out. Now we have Metro Redux, which is a graphical upgrade. Does it seem weird? Partially, because Metro Redux actually has Metro 2033 Redux and Last Light Redux. Metro 2033 was released in 2010 and, although graphically it still looks good even now, it could really use the gameplay improvements form Last Light. Metro Redux also offer that. So then what are the full modifications to the original games?"