Well i really appreciate your effort and think commercially developing and
selling free software is the way to go...but:
The level you showed in the video looks exactly like supertux; same music,
same graphics, minor changes in gameplay.
I'm a huge 2-d sidescroller fan; loved the mario games of course. I also
played supertux1 and 2.
The differences between your game and supertux sound actually not so tempting
("...the game is much shorter.... only ice world" etc.)
I'm not sure, but isn't there a level editor integrated in super tux?
I think the final version of retux will probably be very similar to what
somebody could have done with this level editor except of some minor
differences that don't really matter (at least to me and, so is my guess, to
many other players).
50 000 dollar for this sounds unachievable;
500 maybe, but i wish you the best.
Besides onpon, i don't think it is possible nowadays to make 50 000 with a
mario clone, regardless if it's free software or not.
There are so many out there, everybody has played them and the original is of
course always far superior.
A lot of free software enthusiasts like of course to have a free-mario clone
and that would be a reason to contribute, but...
well, there already is (supertux 1 and 2).
But again, hope you succeed.