Having researched Sun Electronics/Sunsoft for five years, I am really happy to finally see that G.T. Block Challenger have been dumped. I made that Fandom wiki page. The text is not very correct. I am almost finished with my first magazine about Sunsoft, where I cover their old games. So, I will be really happy to make changes to the text so it no longer says it is lost. And some screenshots will be great too.
I took a look at a random skeleton driver and fleshed it out:
It's a "Bingo Pinball". It partially works, but of course it's a bit pointless without ball physics simulation. The service mode is interesting though, it allows you to read and write all locations in memory.