I think you can figure it out, but don't be afraid to ask for help.
Alrighty. I gotta ask for help. When the first alien ship on one level said "blood sacrifice" I was like "OH MY CRAP I THINK I FOUND IT!" But then nothing was that special about level 11 so I may have missed my opportunity.
I think you are the first person to get to level 11 so congrats on that. You don't need to be at a high level to get to the secret ending though.
1111 11!