I saw that it was down to $40USD on steam and went looking around a few other sites and then found it cheaper.
SPECS:
Minimum:
Windows
OS: Windows 7/8.1/10 (64-bit versions)
Processor: Intel Core i5-2400/AMD FX-8320 or better
Memory: 8 GB RAM
Graphics: NVIDIA GTX 670 2GB/AMD Radeon HD 7870 2GB or better
Storage: 55 GB available space
Additional Notes: Requires Steam activation and broadband internet connection for Multiplayer and SnapMap
Recommended:
Windows
OS: Windows 7/8.1/10 (64-bit versions)
Processor: Intel Core i7-3770/AMD FX-8350 or better
Memory: 8 GB RAM
Graphics: NVIDIA GTX 970 4GB/AMD Radeon R9 290 4GB or better
Storage: 55 GB available space
Additional Notes: Requires Steam activation and broadband internet connection for Multiplayer and SnapMap
DOOM is provided via Steam key for Windows. For key redemption, a free Steam account is required.
Developed by id software, the studio that pioneered the first-person shooter genre and created multiplayer Deathmatch, DOOM returns as a brutally fun and challenging modern-day shooter experience. Relentless demons, impossibly destructive guns, and fast, fluid movement provide the foundation for intense, first-person combat – whether you’re obliterating demon hordes through the depths of Hell in the single-player campaign, or competing against your friends in numerous multiplayer modes. Expand your gameplay experience using DOOM SnapMap game editor to easily create, play, and share your content with the world.
STORY:
You’ve come here for a reason. The Union Aerospace Corporation’s massive research facility on Mars is overwhelmed by fierce and powerful demons, and only one person stands between their world and ours. As the lone DOOM Marine, you’ve been activated to do one thing – kill them all.
$37.08 AUD here.
https://www.kinguin.net/product/510363/doom-steam-cd-key/