Wow, nice trailer. Giana's Return is the unofficial sequel to the classic game "The Great Giana Sisters." This is not to be confused with the official Giana Sisters sequel on the Nintendo DS. Giana's Return is a homebrew title being developed by a team headed by Kojote (of PDRoms fame).
I have been in close contact with a couple members of the team, and I have seen the game in action. This is not just some silly little game made by some random hobbyist. I've worked with the main coder before on projects. He is one of the best that I know. Also working on the project are professional graphic and audio artists. This is no Bob's Game, which is all hype. This project has kept relatively quiet, but I think you'll find that it's just as good as many commercial titles. If you know Kojote, you will know that he won't release anything until it's completely ready and perfect.
I expect it to be released on the GP2X to start out. Depending on when it is ready, I'm hoping that it will also be available on the GP2X Wiz. After that, I expect it to be ported to other systems like maybe Dreamcast and such.
If you're still skeptical, just check out the trailer. Does it look like the work of some hack that couldn't make it in the game industry, or does it look like a team of devoted fans have worked on it for several years? I think the answer is obvious.