First, I can only think of one downside to this "overhaul": you can only use the DX9 version of the game. The game comes with a DX10 version as well. As far as I’m concerned, there’s no real difference between the two graphics-wise, but there is one downside: there is no option for more than 60Hz. That means you will get 60FPS locked. But I’m not sure how well 60+ FPS even works in DX10. It might not work properly there either, but I’m not sure.
Is it worth sacrificing that for the "remasterisation"? That’s for you to choose. But if you ask me: a BIG yes, sir!

At the moment, the author of the ReShade has decided to no longer allow his ReShade preset to be used by others. I have tried contacting him but received no answer so far. That means, for the time being, as long as the author wills it, please ignore the ReShade part of my guide (the spoiler stuff). If someday he decides to allow me to share it again, I will gladly update the guide.

Here is the list of stuff you must download. Please download them:

• Overhaul - This mod updates a whole bunch of textures, using unique ones and many from Assassin's Creed: Revelations.
  
• ReShade[drive.google.com] - Brings a new light to the game, one that is much needed.
  
• ME3Explorer[github.com] - An editing tool for the mod. For the mod and ReShade to work together, we need to do some editing. I would just edit it myself, but since I can't get an answer from the author, I am not allowed to share an edited version of someone else's work without his approval.
  
• Original Textures[drive.google.com] - These are the original textures you’ll need to use with ME3Explorer.
  
• LAA[www.techpowerup.com] - A tiny software that will make the executable of the game large address aware. Without this, the mod crashes.
  
• Xbox 360 Fix[community.pcgamingwiki.com] - Fix for the controller.

Let’s first start with editing the mod to fully work with ReShade without problems.

• Open "Assassins_Creed_I_Overhaul_2016_Full_Version.rar", then open the folder and extract "Assassin's Creed Overhaul 2016 Full Version.tpf".
  
• Extract the 2 files inside "textures.zip".
  
• Fully extract "ME3Explorer_dev_718.zip", then open "ME3Explorer.exe" from inside the "ME3Explorer" folder.
  
• Way up in the tab you have User Tools, click it, then Textures -> TPF/DDS Tools.
  
• Ignore the DebugWindow by minimizing or closing it, and focus on the newly opened window: "TPF/DDS Tools 3.0: ME3".
  
• Click on "Load" and select your "Assassin's Creed Overhaul 2016 Full Version.tpf". Wait until the loading process has finished.
  
• Scroll down until you find the texture: "ASSASSINSCREED_DX9.EXE_0x11D2D4DD.bmp", then select it and click "Replace" (look down, above the 4 big buttons). Choose the texture file corresponding to the name, that you extracted earlier.
  
• Repeat with "ASSASSINSCREED_DX9.EXE_0x2247F0FF.bmp".
  
• Click on "Rebuild TPF" found at the top, then select Yes and wait. A TexMode Beta window will open by itself and start building the file. Don't move your mouse, just wait until it finishes.
  
• When it is finished, it will ask where to save the file. Save it in the main folder of the game (ex. C:\Program Files (x86)\Steam\steamapps\common\Assassins Creed) and call it "Overhaul Fixed".
  
• You can now close the tool we just used and even delete the 2 texture files, the original .tpf mod file, and the "ME3Explorer" folder.

The hard part is now finished. As I said, if I could somehow contact the author, I would have just uploaded the fixed mod file and not made you go through all of this. But anyway, let’s move forward.

• In the main folder of the game, extract "laa_2_0_4.zip", acii_wireless_360_fix_by_khemitude.zip, and (previously) the contents of the folder "AC1 ReShade" (NOT the folder itself) inside AC1 ReShade.zip".
  
• Open "Assassins_Creed_I_Overhaul_2016_Full_Version.rar" again. Inside the main folder, you will find "Texmod and opentexmod", and then "Texmod OLD not recommended". Extract "Texmod.exe".
  
• Rename the extracted file to "AssassinsCreed_Game.exe" and copy/paste it into the main folder of the game. You’ll be prompted if you want to replace the file, please do replace it. (This allows you to launch the game through Steam instead of launching it externally.)
  
• Inside the main game folder, we extracted a file called "Large Address Aware.exe". Please open it.
  
• Select "AssassinsCreed_Dx9.exe", check the tiny box, then save.
  
• Repeat with "AssassinsCreed_Dx10.exe" and "AssassinsCreed_Game.exe".
  
• You can then close the tool.

I will now humbly ask you to launch the game through Steam.
You will now notice that the TexMod tool has opened:

• Click on the bigger folder icon and choose "AssassinsCreed_Dx9.exe".
  
• In Package Mode, click on the tiny folder icon, "Browse", and choose "Overhaul Fixed.tpf".
  
• Make sure the file is selected, and click "Run".
  ** You have to repeat these steps every time you start the game, but next time TexMod opens, it will already have the .tpf file in the list. You can directly choose it from there instead of browsing for it.
  
• After the game launches, go into Options, set all the Graphics Settings to maximum (for some people there is better performance with 60Hz resolution + VSync ON, feel free to try it). Choose in Controls Options your controller if you wish to play with one. (There used to also be a bug, don't know if it still is the case, but just in case, I suggest you make sure you have "Hold to Lock" turned OFF.) Save the settings and turn the game off. After it closes, you can also close the TexMod tool that was open.

• Please now go to: "C:\Users(USER)\AppData\Roaming\Ubisoft\Assassin's Creed" and open "Assassin.ini".
  
• Search for "Multisampling" and change the value to 2, then save the file. (There’s a bug inside the game settings, which is why we do this. The game won’t allow you to change multisampling if you have a higher resolution.)
  
• You can also make the file read-only so it won’t change if you modify settings in-game.

You are now done. You can enjoy the fully fan-made remastered version of the game. ^^
I hope you like it! Have fun!

And remember: nothing is true, EVERYTHING is permitted!

• hecumarine (Overhaul)
  
• crosire (ReShade)
  
• schnitzeltest (Preset for ReShade; Mod Fix for ReShade)
  
• ME3Tweaks (ME3Explorer)
  
• FordGT90Concept (LAA)
  
• Khemitude (Xbox 360 fix)
  
• RS (TexMod)
  
• PCGamingWiki (fixes)