Another way to increase performance of Gruntz on Windows 10

[swietymiki]

For several years now, we thought that the issue with running Gruntz from Windows 8 and up was that the operating system lacked the functionality to properly emulate the old DirectDraw API. It turns out that we were wrong...

I semi-randomly stumbled upon a thread of a different game on the GOG Forum, where one post explained how to assign some compatibility flags to an exe file in the registry. I tested them and some others with Gruntz and, to my surprise, I managed to get the game to run really smoothly, without having to download any additional files or programs. So I made this short tutorial to show you how to get the same effect.

1. Run regedit.exe. The program will ask you for administrator privileges.
   
2. Navigate to the folder \HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers. You should already have an entry for Gruntz in there, because Windows applies one flag related to the game's color mode automatically. But in case you don't have it, right click and create a new string value with its name being the path to the game's executable.
   
3. Double click on the entry for Gruntz to change its value. Set it to $ DWM8And16BitMitigation 8And16BitAggregateBlts Layer_ForceDirectDrawEmulation and click OK. The first flag can also be skipped as it's added automatically (in my case at least). Your game should be working smoothly the next time you start it.
   

But where's the catch? In our Gruntz community, we have grown accustomed to workarounds that are not perfect and this one is no exception. You need to be aware of some (relatively minor) issues this solution has.

First, there are some graphical glitches. You will notice that the cursor leaves a residue on the sidebar when you move it quickly. This can be cleared by switching to a different panel though. You may also experience flickering of some parts of windows that you have open, on your Gruntz map. This can obviously be fixed by closing those windows before starting the game. Also it appears that those issues can be mitigated by launching Gruntz with Windows XP compatibility mode, with the trade-off being that the game works a bit slower overall.

Second, Gruntz doesn't tolerate alt-tabbing well under these compatibility flags. With Windows XP compatibility mode, upon returning to the game you will be greeted with a nice corruption effect with misplaced objects and transparency turned to pink. With no compatibility mode, your game will quietly crash when you try to open it again.

So go ahead and save your game like a little baby before you decide to tab out of the game to do something else!

[Lahyme]

This is crazy man... LOL

[GooRoo]

Either my computer does not have the URL string given in your example, or Windows 10 simply does not allow File Explorer access to reach it (security issue), but is only accessible via RegEdit. After lunch I will try again with RegEdit as per your write-up.

Supposing that is successful, should the various earlier work-arounds (dgVooDoo, setc.) be deleted?

[swietymiki]

You'll need to get rid of the DDraw.dll file (at least temporarily) to notice a difference. Otherwise the game is going to run with dgVoodoo and not use these registry settings.