Credit for this guide goes to both puhgee and Semorpen.

Thanks to them I found a fix that works pretty well and I thought I would share this with everyone else.

1. First go to this site to download the latest version of DXWind[sourceforge.net] (it was 2.06.04 at the time of writing)

2. Go into the games files and delete the version of DXWind it game with.

3. Extract the latest version into the games folder (To make the process faster you can excluding exporting the exports folder). If you did everything right so far it should look like this:


4. In the games files rename the d3d9.dll, ddraw.dll and dxwnd.dll files by adding a 2 at the very end (ex d3d9.dll2 - this should make the game ignore them)

5. Open the v2_06_04_build folder and run dxwnd.exe as an admin.

6. Go to the options tab and click on Extended Mode.

7. Then go to Edit and click Add.

8. On the main tab file in the following boxes.

Name - Sherlock Holmes: The Mystery of the Mummy
Path - click the ... and go to the games folder to select the game.exe file
Launch - click the ... and go to the games folder to select the game.exe file

9. At the very bottom change the W and H values to match your native resolution.

10. On the bottom right change the selection from "X,Y coordinates" to "Desktop".

So far it should look like this:


10. Go to the Mouse tab and set Mouse Clipper to "On".

11. Check both boxes to Invert the mouse x and y axis.

12. Under Cursor handing select the options "Keep cursor within window" and "Keep cursor fixed".

13. Go to the Tweaks tab and in the list of Available tweaks look for input:MouseMoveByEvent.

14. After you select it press the green plus sign and it should move it over to the Active Tweaks window.

15. Press the "OK" button at the bottom.

16. You should now see the entry you just created. Click File and choose save and click Yes.

Whenever you play the game make sure DXWnd.exe is running as admin before you press the play button in Steam. If you don't then the game will launch with black blank screens.

For some reason there is something that causes the cursor to hit an invisible "wall" when moving it around which can prevent you from looking around in a certain direction. It can normally be fixed by moving the cursor around the screen a couple of times. If anybody knows how to prevent that please let me know in the comments :)

Update
I have found that it happens less for me with the following options selected:

Not sure if it actually helps or not but I am leaving it enabled haha.