There were many changes between the first and second Academy Awards. The number of categories were reduced from twelve to seven, while the number of nominees allowed in each category was increased from three to five.
Not that that mattered, because the nominees were never announced, just the winners.
It was the first Academy Award ceremony broadcast by radio.
Finally, it was the first of two Academy Award ceremonies to be held that year, so that it might fix itself so that it awarded films that fell in the calender year.
The film world was in a state of trying to find itself again. The introduction of sound crippled the silent industry (though a number of silent films still got nominated that year). People were leaving and entering the film industry at an alarming rate, and what was once box office gold was now ignored while a whole new wave of films began to be noticed.
I'm not sure how much of this chaos effected film availability from that year, but I cannot find any more then six nominees from the 2nd Academy Awards, and I don't know, but that might be for the best. The earliest of sound films were not pretty.
Welcome to the 2nd Academy Awards. What's left of it, anyways.