(NOTE
I recommend installing the following mod first: https://www.dixmor-hospital.com/mods/view/manhunt-2-all-weapons-in-all-levels
This way, the tutorial will be easier and faster.)
Tutorial:
1-Open Manhunt 2TEX/EDITOR
2-Click the "Open" option
3-Locate your Manhunt 2 game folder
4-Open the folder named "Global"
5-Open the file named "gmodelspc.TEX"
6-Find the files named "Shard" and "Shard2"
7-Replace those two files with the new texture
8-DONE
(I'll be uploading more mods with remastered or HD textures, so stay tuned for more :b)