Halo: Combat Evolved was design for the old style CRT monitors that were commonly used untl LCD panels completely replaced them. Halo has command line options to run it at any resolution but shortcuts in Windows Vista and above are tricky to configure.
We developed a simply loader to run Halo at the current desktop resolution. This way the game can be played at higher resolutions easily. The game is not very deimanding by modern standards.
While video cards like out HD 6970 and GTX 660 Ti are not designed to operate at 3820×2160 etc, the the game is not very demanding and it’s possible to play at very high rsolutions.More recent video cards now feature HDMI 2.0a which is more suitable for ultra resolution panels.
DisplayPort is not widely seen with most LCD panels however its bandwidth makes it possible to run Halo at very high resolutions smoothly.
Simply unzip the loader and place in the folder with HALO.EXE. The make a shortcut to the desktop and now Halo will run properly like modern games.