"I conceived, designed and implemented a compelling prototype for it almost single-handedly, and then wrote a fair percentage of the production (...)"

I do this all the time, and have done it many times in the past. For some folks, it's really not a big deal, and not even rare/uncommon. Some people are idea rabbits and can spew out architecture/code, new products, etc. Some can't. Some are shades of grey.

Also, I'd rather see people be honest about the things they can do, than be dishonest about what they can't.