This tool can be used to monitor the dynamic difficulty level, and various other memory values from Resident Evil 4. It has only been tested with the latest steam version (bio4.exe version 1.0.18384.1 md5:ac6abb25e476b65b4f363247bd205217) and probably won't work with any others.
The intended use is for speedrun practice/learning (NG Normal).
The latest compiled version can be obtained here, it requires the .NET 4.5 framework to run.
Just open the executable, it will monitor the current instance of bio4.exe. You can also adjust the dynamic difficulty value by right clicking and choosing "Edit Difficulty Scale".
If anyone has any problems and/or feature suggestions either leave a comment on github or tweet @omrulg