DaveScott005: I found GOG today and am just amazed by the abundance of classic games that are available.
But with a new Windows 10 PC, i am puzzled that games I played on Windows 95, 98, and XP, such as Apache Longbow, RR Tycoon 2, and Silent Hunter, can function on Windows 10. How is this possible?
Lots of different reasons combined:-
+ Backward / forward compatibility is still one overwhelming natural platform advantage of PC gaming vs consoles in the first place. x86 PC hardware is architecturally stable and static whilst consoles have used all sorts of different architectures over the years (MIPS / RISC, hardwired cartridges, etc, which aren't compatible from one generation to another).
+ DirectX and OpenGL are backwards compatible. An OS designed for DX11 (W7) or DX12 (W10) will still play DX6 to DX10 titles), and games written for say DX7 will run on DX11-12 GPU's. I'm still playing DirectDraw 5-6 games like Commandos Behind Enemy Lines, Age of Empires 1-2 and Diablo 2 even on W7-W10. Although W10 has "deprecated" DirectDraw for the first time, it can still be re-installed with Control Panel -> Programs -> Turn Windows Features on or off -> DirectPlay.
+ 64-bit OS's still have native 32-bit support. They've only dropped native 16-bit support...
+ ... But that lack of native 16-bit support can be worked around, eg, 32-bit games that used a 16-bit installer have newer 32-bit installers. Likewise, DOSBox and ScummVM will run a lot of 16-bit (pre Win95) DOS games in a new native 32-bit "emulator" that works perfectly on 64-bit OS's
+ Source-ports. Games like Doom 1-2, Heretic, Hexen and Quake play better than ever in new OpenGL ports like GZDoom or Quakespasm.
+ Many games have been patched to have DRM removed. W10 broke SecuRom but if you strip that DRM out, the games themselves can still run fine
+ Modding community updates. Games like Thief 1-2, System Shock 2 or Deus Ex (Direct X7) have been updated to newer DX9-10 renderers. Effects like Bloom, native widescreen resolutions, adjustable FOV and HD texture packs have been added too.
In fact, Thief (1997) has gone from looking like this :
http://i.imgur.com/Dlccc7y.jpg To this :
http://i.imgur.com/90jdHB6.jpg Really there's several reasons combined (rather than one big reason) why older games are not only still playable but some are playing better than ever.