Like for others, for me, this was the first strategy game I played, which makes it unforgettable for me.
While it has a simple premise when compared to the likes of CnC or Warcraft, with only vehicles of various kinds and no infantry at all and no special abilities, there is a surprising level of care needed - for example, your vehicles can and will run out of fuel if you don't top them up, meaning you could see a whole tank squad stranded in a conga line because you forgot to refuel them before sending them on the next assault.
The superweapons (nuke, buzz bomb, toxin launcher, kamikaze) also present an interesting choice -- they are very powerful BUT each use detracts from your final score, so they are best used to break stalemates.
I also like the lack of clear rock-paper-scissors dynamics in regards to land units, using power, resilience, cost and speed to balance them instead -- e.g. Heavy Tanks will tear through absolutely everything but are painfully slow, so they can be swarmed by lighter units if you send them on their own, and they cost a lot, so you really don't want to do that.
Preserving this on GOG would let a new generation experience this hidden gem of a strategy game.