Hi,
First off, that ISN'T a HIND-D. Notice how the HIND-D has twin bubble canopies:
Now watch the trailer again and look at the canopy... it is a single large, square canopy and the two sections of it run flush with each other. My knowledge of postwar Soviet aircraft is not very good, and my searches on Google don't reveal what type of chopper that is, but it ain't a HIND-D.
Second, Infra-Red technology was very well developed by 1964. IR technology was in use in WWII with the Germans who developed it during the war, and it has been used and refined since 1945.
I agree on the hovercrafts, though. IMO it would've been much cooler for them to stick to the technology of the time, and that's it. Man, I'd love for them to do a version of MGS during WWII, with perhaps an earlier operative fighting the Germans? That would be kickass!
Look at those flame effects! Wow! And was that last guy Raiden? Sure looked like it. Pretty funny on that last part, too. I like that way the guy says, "Kuwabara, Kuwabara..."
Thanks,
Manga