That doesn't surprise me. Biology was never my strong subject. Chemistry is; and that is why I'm study to be a chemical engineer. :D
Which parts are wrong, out of curiosity?
Very cool. I am Chemistry major.
The 50:50 DNA from mom and dad is not necessarily true. In the case of a male, the Y chromosome (from dad) is significantly smaller than the X chromosome. Also, not everybody's DNA is the same length.
Genes being determined the moment the sperm and egg combine. Mutations can, and do, occur early on.
Genes not being able to be changed. A retrovirus could do it. (Not practical)
Chromosomes changing slightly = death of cell, not necessarily. Estimates put upwards of 90% of DNA coding for nothing. Most changes in DNA do nothing. Some will kill a cell. Some will make it function incorrectly. Some will make it better.
It's really all just nitpicky stuff.