This Dutch Aleste-like game by MSX-Engine came in a big (videotape) box, containing the game-disk, a storybook, and synth re-arrangements of the soundtrack on tape.

Everyone I know (quite a number of people) who, like me, had an original copy of this game, lost the tape at some point, never to find it again.

So...

I think we have an interesting mystery here!
Anyway, I assume we can all agree, with the cold, hard facts speaking for it, that this particular tapes are somehow able to grow legs, as that's the only logical explanation.
Elementary, my dear Watson! (No shit, Sherlock!)
The big question is, where did they run off to?

My guesses are as good as yours. Or worse.

(1) The tapes are supporting themselves by eating insects in a garden or park near your house.
When they meet another runaway tape, they might mate and create more tapes.
(which would imply they grow more than just legs)

(2) The tapes were programmed to run back to Loek van Kooten's (MSX-Engine composer/developer-guy) place.
He puts them in a really big safe and gloats over them on a daily basis.
He might even take a swim in the stock of returned tapes, sort of Scrooge McDuck-style.

(3) Like (2), but MSX-Engine simply re-distributes the tapes to new buyers of the game.
After a given period. the tapes escape from their new owners, and the whole process starts over again.

Probably, option (3) might be the least naive theory.
Business is business, you know...

Anyhow, this is surely a display of impressive enineering from the MSX-Engine guys!
Tapes that grow legs... One might think it's impossible if it wasn't for them guys.

P.S. Ofcourse I systematically disbelieve anyone claiming to still own the D.A.S.S. tape!

I think the answer is more mundain. Those lost tapes are very much like lost socks and feed your local time-space vortex...

/me checks box: darn! How did it escape??

Yup, mine has escaped as well

Can't remember that tape but it's not in the box so mine is gone too.

No tape here either... I think that it might be possible that these tapes have a manufacturing flaw that made them stuck to the timeline. In this case those tapes might still exists in the original time of production.

Hmm.. I think I did recently see the cassette's casing lying around somewhere.. not sure if the cassette itself was still in it..
maybe I should clean up here again and see if I can find it
Maybe it is a sign that Engine Software is creating a new D.A.S.S., for the DS perhaps, like konami is doing a new track 'n field?

Well, quite a while ago they did had some ambitions towards PlayStation...

Anyway, if they're really going to release a new D.A.S.S. they'll probably include a CD which grows wings.