Generally, if your computer can comfortably run Windows XP then you are fine. Verge3 works with XP, 2000, and 98 (and possibly 95, unconfirmed at time of writing). Maped 3 (which is included in the Current Engine package and is needed to create maps) requires that you have the .net Framework installed which you can find here
Well the requirements, aren't that high:
Operating System: Windows 98
Platform: Pentium 166 mhz (NO MMX SUPPORT)
Sound Card: Creative Labs Vibra 16
Video Card: S3 Trio (NO 3D SUPPORT)
Hard Drive: Seagate 8 GB
64 MB RAM
16x CD Drive
Lags at Flash, and lack of MMX support screws me over for many features. But this computer still runs VERGE. Check it out: