To attract potential sponsors You need to show something more advanced. I understood that final product is too much. Demo we could play would be great, or just a slice - short movie showing gameplay from few levels. Stuff that look nice also could work, like concept art, early shoots of sprites and graphics, comparison shoots showing game with placeholder sprites and finished ones. Show video how You draw sprites or write a bit of code. Offer something to those who support You - like if You pay that amount of money You could design Your own sprite for game or other graphic, and if You pay more You can draw a map of level and I will create it in my game.
Right now there isn't much to show. People buy ideas, but mostly if there is some certain point of progression already done. Like with "Tower 57" and if there is nothing to see, like with new Dizzy and James Pond on kickstarter, people will not trust and not support.