CouponSome versions of Red Baron II included a coupon inside redeemable for a free Red Baron Premium brand Pizza. Amazingly, when online video game reviewer Clint Basinger of Lazy Game Reviews tried to redeem said coupon 17 years later, it turned out to still be valid. You can find the video here.
PatchSierra eventually released a patch for Red Baron II that fixed most of the glaringly obvious bugs and provided 3D support (hence the name change to Red Baron 3-D).
Information also contributed by Amayirot Akago and WildKard