I figure that Casper Van Dien just wasn’t a very good voice actor, so they hired a professional.
The fun thing about the voiceover from the trailer, is that it misquotes the book in a way that entirely changes the context. In the movie, the quote has Rico comparing himself to a horse at the gate, shaking because he’s eager to race. The quote from the book is:
Didn’t Sunrise get sued over that anime? Like it wasn’t an authorized adaptation? In any case, I’ve seen the suggestion made that the entire Mecha genre of Japanese film might have been inspired by Starship Troopers (same could be said for the same genre in Western media, though it was never as popular over here).
But yeah, Invasion is a sort of blend of elements from the movie, the book, and the cartoon series. It mostly plays like the cartoon and the movie had a kid.