Yeah, you're way ahead of us on the "does our proof fit in a tweet" metric! How did you get 72% of the bits to match, is there a writeup anywhere? It's very impressive. Algabraically, it seems you'd need about 2 million hashes, and around 2 million million (10^12 = 2 trillion) comparisons to go through all of them. Did you just put in the computing time, or did you use any algabraic properties?
Since you've made hashes that match at the beginning and end, you might also be interested in our exploration of alternative presentation formats that make attacks like this a little bit more difficult. We were working on a new hash and thought about how to assist people visually at the presentation level. This one tests your speed versus a typical hex presentation.[1]
https://news.ycombinator.com/item?id=38668893
(Also my work does not demonstrate any weakness in SHA256, it's just an application of the birthday paradox)