Any ideas on system requirements?
That's something I can help with as the spec is now up on the official store page. As we're now not that far off release, I don't imagine it will change much, if at all (although if it does, I am not to be held responsible - this is the situation as understood for launch and may change).
PC Recommended System Requirements
Operating System: Windows 7 64-bit or Windows 8 64-bit
Processor: Quad Core 2.3GHz or equivalent processor
Memory: 4GB System RAM
Hard Disk Space: 60GB free HDD space
Video Card: Direct X 11 compliant video card with 2GB of RAM (NVIDIA® GeForce® 560 Ti / ATI Radeon™ 6950 or better)
Sound: DirectX compatible sound card
PC Minimum System Requirements
Operating System: Windows XP 32-bit
Processor: Dual Core 2.0GHz or equivalent processor
Memory: 2GB System RAM
Hard Disk Space: 60GB free HDD space
Video Card: DirectX 9.0 compliant video card with 512MB of RAM (NVIDIA® GeForce® 8800 / ATI Radeon™ 2600 or better)
Sound: DirectX compatible sound card
MAC Recommended System Requirements
Operating System: Mac® OS X 10.7.0 or later
Processor: Intel® i5
Video Card: NVIDIA® GeForce® GT 650M or ATI™ Radeon™ HD 5770 or better
Memory: 4GB Ram
Storage: 60GB
Media: DVD-ROM
MAC Minimum System Requirements
Operating System: Mac® OS X 10.7.0 or later
Processor: Intel® Core™ 2 Duo
Video Card: Intel™ HD Graphics 4000, NVIDIA® GeForce® GT 330M or ATI™ Radeon™ HD 6490M or better
Memory: 4GB Ram
Storage: 60GB
Media: DVD-ROM
Resolution: 1024X768 minimum display resolution