That looks like a really nice Giana Sisters remake there Jon.
It's a cool topic too, I have been affected by this problem myself many times, before DBF started I'd often work on routines to do all kinds of things, I'd have over ambitious ideas for something and they never came to fruition.
The advent of this forum kind of solved the problem for me though because everything I work on that comes to the end of its useful life(when I realise that I dont have the skill to conclude it, or that it is not as cool as I thought, or even when I lose interest in it), invariably all that source ends up on this forum, it's been so useful for me too.
Sometimes I might have another idea and realise that I could reuse something I had partly done and put on the forum so I am forever nipping on here and pinching bits of my own programs so I can argue that nothing I ever do is finished

The worst ones that really stick in my throat are collaberations between other coders.
I've never had much success on joint productions, the only one that I ever finished (as far as I can remember) was a little intro I made with Ferris or Blitz Amateue (cant remember who it was, sorry!). I made a plotball and he made a vector scroll, I dont have a copy of that any more.
The most notable failures were:
The forever doomed RPG project on the Yabasic forums (I made an engine for it but nobody completed it, this was in development for years!).
Dark Bit Factory Book Of Visions, A colaberation between me, Stonemonkey, Wham and Roly. This was sad because it actually was looking really promising, It was using stonemonkeys engine, a few effects by me, music by Roly and gfx by Wham... It began well but the project ran out of steam and just ground to a halt.
Again I don't have any of the stuff for this project any more.