There is yet another key change. It is now in B major instead of C major. The reason for this change is uncertain.
Also, a new verse has been added - not at the end, but at the beginning ("Living is easy with eyes closed..."). This brings the total number of verses to three, all of which would be retained (albeit slightly modified) through the song's release.
The biggest changes, however, are in instrumentation, because now for the first time the song is played by the band instead of just Lennon by himself. In addition to Lennon's guitar and lead vocals, Paul plays the mellotron (a predecessor to the modern-day synthesizer), George played around with his slide guitar, and Ringo adds percussion. Additionally, backing vocals are added to the third verse ("Always, no, sometimes..."). (Note that on The Beatles Anthology these harmonies are inexplicably removed. The version found on the album It's Not Too Bad retains those backing vocals, and that is the version above.)
Lastly, the coda has been greatly expanded - an instrument closing featuring Paul's mellotron playing that will ultimately be used as the intro instead of the outro.