I've finished the patches for keropi. See attached files.
Please note that these patches only work for one specific version of each game. That's version 1.4 (Apogee release) for Keen 4 and 5, and version 1.5 for Keen 6.
First of all, download CKPatch v0.11.3 here.
Download my patch scripts, then extract my patch scripts (PATCH?.TXT and CK?.BAT) into the game's directory. Also copy the corresponding CK?PATCH.EXE into that directory. To play the game, simply run the CK?.BAT file.
I'm not sure what happens when you try to run these patches on the wrong game version, so make sure you're using the correct version of the game when trying to run these patches. If I understand the syntax correctly, the patch scripts should only modify the code of the correct EXE, so if you try to run it on version 1.0, it should not change anything, but I haven't actually tested this.
By the way, I added the original assembly code as comments in the patch file, so you can see what's going on in the screen update code. If you know a bit about programming in assembly, you should be able to modify the patch for better results on your system.
Edit: If CKPatch shows an "unrecognized version" error, try unpacking the executable with UNP or UNLZEXE.