The Manhunter games are DOS-based and were programmed in the late 1980's using Sierra's AGI (Adventure Game Interpreter) development system.  Through the years, AGI has proven itself to be a remarkably stable platform.  Even today, the fastest computers will generally run AGI games with few or no problems.

However, some game functions (such as software loops) may be tied to the speed of the computer's CPU.  While this is fine on slower systems, faster computers will execute these loops too quickly.  An example of this can be found in the Flatbush Bar in Manhunter: New York.  If you accidentally hit the bartender's finger with a knife, today's computers will flash the resulting image of his grimacing face too quickly to see.

One solution to these issues is a DOS emulator known as DOSBox.  Among the many benefits of playing older games through DOSBox is the fact that it has a configuration file (dosbox.conf) that can be edited to play the games in Tandy mode.  The advantage to doing this is that Tandy mode features 3-voice music and sound instead of the single-voice tones and music characteristic of earlier IBM computers and other older PC clones.  DOSBox can be downloaded from this site.

Another option is a development system called NAGI (New Adventure Game Interpreter), which was created by reverse-engineering Sierra's original AGI system.  It is specifically designed to run in Windows and also offers Tandy 3-voice emulation.  NAGI is another excellent choice for running AGI games - both official and fan-made - and can be downloaded from this site.