There are definitely some major implementation level differences between Ethereum and Bitcoin.  The hashing mechanism (Ethash) is quite different from Bitcoin, as well as how references to previous transactions are stored.  You can read more about it here [1] and here [2]<p>[1]: <a href="https:&#x2F;&#x2F;ethereum.gitbooks.io&#x2F;frontier-guide&#x2F;content&#x2F;" rel="nofollow">https:&#x2F;&#x2F;ethereum.gitbooks.io&#x2F;frontier-guide&#x2F;content&#x2F;</a><p>[2]: <a href="http:&#x2F;&#x2F;gavwood.com&#x2F;paper.pdf" rel="nofollow">http:&#x2F;&#x2F;gavwood.com&#x2F;paper.pdf</a>