It definitely looks like Mech2 Mercenaries 1.00/1.05 PC for DOS/Windows. The fake "3Dfx" version (which is still Direct3D) has a grey CD cover. If my guess is correct, then yes you have the option to patch it for Direct3D hardware acceleration. Patch up to 1.06 to retain DOS/Windows version without hardware acceleration and you can still play the DOS version in DOSBox. Version 1.08beta is the 1st version of Direct3D patch, it kills the DOS version after patch and retains the original scripted salvage gameplay. Patch 1.1 is the final Direct3D version and it alters the gameplay to dynamic salvage (but buggy somehow...)
However, Pentium 200MMX/Win98SE/TNT2 may not play the game at 30FPS with the Direct3D version but rather low FPS, especially when particles and chunky explosions are enabled in graphics details. You can disable that 2 graphics options for significant increase in FPS.