The bomber variant is a different one from the one we have. It had (from memory) 2 of the 30mm removed to save weight in the nose, because the bombs were strapped under the nose.
The big arse cannon was simply a test bed, and the unit was almost unflyable, but it worked.
However, the biggest gripe I have (okay, SECOND biggest gripe I have) about the 262 in AH is that it doesn't have the R4M rockets. They would be far FAR more lethal than the WGr 21 rockets we have now, and there'd be about 24 of them for a single plane (as opposed to 4 max for the WGr on the 110G-2).