Official specs from Steam

Metro: Last Light system requirements

Minimum and recommended PC specs as listed by the developer on Steam. Native macOS version available. Native Linux build available.

Minimum

OS *Windows XP (32-Bit only), Vista, 7, or 8
ProcessorDual Core CPU (2.2+ GHz Dual Core CPU or better)
Memory2GB
Hard Disk Space
Video CardDirectX 9, Shader Model 3 compliant graphics cards (GeForce 8800 GT 512 MB, GeForce GTS 250, etc)
DirectX®9.0c
AdditionalMetro: Last Light utilizes NVIDIA 3D Vision with compatible cards and hardware.

Recommended

OS *Windows 7 or 8
ProcessorAny Quad Core or 3.0+ GHz Dual Core CPU
Memory2GB
Hard Disk Space
Video CardDirectX 11 compliant graphics card (GeForce GTX 480 and above)
DirectX®11
AdditionalMetro: Last Light utilizes NVIDIA 3D Vision with compatible cards and hardware.

macOS minimum

OS10.8.4 (Mountain Lion)
Processor2.7 Ghz Interl Core i5
Memory8GB
Hard Disk Space10GB
Video CardNVIDIA GeForce GT 640M 512 MB

macOS recommended

OS10.8.4 (Mountain Lion)
Processor3.2 GHz quad core Intel Core i5
Memory16GB
Hard Disk Space10GB
Video CardNVidia Geforce GTX 680MX with 1GB

FAQ

What graphics card do I need for Metro: Last Light?

Minimum: DirectX 9, Shader Model 3 compliant graphics cards (GeForce 8800 GT 512 MB, GeForce GTS 250, etc). Recommended: DirectX 11 compliant graphics card (GeForce GTX 480 and above).

How much RAM does Metro: Last Light need?

Metro: Last Light needs 2GB at minimum, 2GB recommended.

Does Metro: Last Light run on Mac or Steam Deck/Linux?

Yes, there is a native macOS version. A native Linux build is available.