I know that it's hard but from what I've seen most people (me, internet strangers, friends) can generally get past level 10. I think that the "textures" (=graphics, it's not a 3D game) are very minimalist, which is a style I have adopted. I recognise the importance of graphics, but I will point to very successful games with minimalist graphics:
http://thelettervsixtim.es/ (not totally minimalist but still pretty minimalist)
Ultimately considering the fact that my last game took 29 days to make, I wouldn't be able to make the 30 day deadlines anymore.