Thank you for your answers.
Yes, I discovered it's quite a beast to ride, but the graphics look good. For the rest - we are busy little beavers and may pull it off within the given time. We can adress Source via C++, intending to use it for handling dialogue choices and effects. We are looking into interconnecting VCDs to actually represent the dialogue. Perhaps this sounds even wilder to you than to me since I have just begun to explore this thing.
If we won't pull it off, we can at least showcase the artwork.
@Tetsu: Goldsource? Is that the old HL1-engine? I don't think this would be up to at least fairly recent graphical standards. Our presentation would then... disappoint some people...
Thomas