You might want to read through the changes before installing as this mod comes with a few optional files.
https://pastebin.com/pMe9Jak6

- resource1.glg (controls what player model to use in the level)
- modelspc .mdl/.tex (models that are used in the level, this mod changes the cutscene actors' models)

Installation

1. Replace the files of each level
[Manhunt 2 Directory]/levels/
2. If you wish to use the optional files, it's the same as step 1 except for a few.

- resource3.glg lists all the entities and execution timings
This can be a problem for a variety of reasons, most notably Extended Executions compatibility.
Select the resource3 of your choice, whether you play with unmodified PC executions or Extended, they are not cross-compatible!

Level List:
Awakening - A01_Escape_Asylum
Ghosts - A02_The_Old_House
Sexual Deviants - A04_SM_Nightclub
Red Light - A07_Tolerance_Zone
Best Friends - A14_SugarFactory
Safe House - A07_2Tolerance_Zone
Bees' Honey Pot - A10_Brothel
Assassination - A12_Plaza
Most Wanted - A06_CIA_Trap
Ritual Cleansing - A09_Burn
Origins - A11_Medicine_Lab
Broadcast Interrupted - A16_TV_Studio
Altered State - A17_Creepy_Farm
Domestic Disturbance - A03_Neighbourhood
Personality Clash - A15_Cemetery
Release Therapy - A18_Manor