I started soak / regression testing on the London Show Pi's yesterday and have detailed all issues in the OP. If you have time, could you see if you're seeing the same issue as I am. BlowPipe showing the same keyboard issues as Wolfenstein 3D, and Gribbly's Day Out having similar scrolling issues to James Pond II is interesting.
Essentially I'm testing games to run in the games Arcade, so I won't be testing all games.
I'm also looking into palette issues, in particular the mouse cursor which looks okay for game set cursors, the default OS HourGlass however isn't setting one of the colours. You can repeat this by mounting a multi-floppy game, hit F12,
*ADFRemapVideoMemory 13 160 and then swap between discs.
Sensible Soccer also does odd things with the palette during the intro, I'm starting to suspect I'm getting rogue palette changes from the OS. I have previously reported an issue in RISCOS, but have not confirmed it was ever resolved - it was a good year ago that I reported rogue palette changes in 4bpp MODE's.
EDIT:
I'm also looking into palette issues, in particular the mouse cursor which looks okay for game set cursors, the default OS HourGlass however isn't setting one of the colours.
I've now raised this as a bug in the OS, it's only passing palette entry 3 when the Hourglass is turned on.
EDIT2: Battle Tank not working appears to be an OS bug, which I've now
reported. Ballarena seems to work okay on my Dev Pi, but not on the London Show Pi's
EDIT3: Rockfall only working under the debug build looks like a Page Zero access bug in the Voice Generator. The debug build might just be slow enough to delay the Channel Handler IRQ until after the bars have been setup.