Yep, Firepower is a classic.
I have looked everywhere for a HD-installed version but I don't know if one exists...if someone has such HD-installed version ("cracked version" or not) it they might consider uploading to the Zone.
There were apparently 2 others in the "One-on-One" series: the game "Turbo" (heaps of fun) and "Galactic Invasion" (haven't played this yet). Turbo runs fine straight off the harddisk even under OS3.9, you can download it from my site.
I've also played "Return Fire" on the 3DO, this is excellent, basically it's Firepower 2, with the ability to control a jeep, helicopter, etc. as well as the tank. Apparently "Return Fire 2" (Firepower 3 :-) ) is also available, for IBM-PC at least, haven't played this as yet.