But back on topic!
Thanks a lot for that long list of descriptions why certain levels from the old "Contributions" package are (most probably) not solvable. (And as far as I can see, these levels are exactly those which do not have solution tapes, and for a reason.)
Maybe this list could be used to fix those unsolvable levels, to improve the level sets (which sometimes have a lot of solvable levels, so one would expect all other levels from the same set to be solvable, too).
I also find it very interesting and a lot of fun to watch other people's solution tapes (especially as I'm a notoriously bad player; no, really!). So it would be nice if this could be made a little bit easier.It's good to see different ways of solving things.
If you want to see any tapes that I've done, feel free to ask. 
Well ... I'm currently working on something that goes a little bit in such a direction: A high score server for R'n'D [...].
[The rest of this post and related follow-ups have been moved to its own topic in the "New Ideas" section.]