I have very fond memories of this game and I've been meaning to replay it for roughly two decades now, but I've long lost my CD with it and even around 2010 when I had found it again it wouldn't run on my computer at the time.
I loved this game as a kid despite the fact that I generally prefer RTS games, but I found the battle system accessible and fun enough, and the world caught my interest with its weird aliens, cool vehicle designs, the different planets and their ambiance, and the campaign was on the whole pretty fun from what I remember.
I thought the ability to upgrade and then carry over some of your vehicles was cool and just in general enjoyed the idea of all-vehicles battles. No infantry, just cool tanks and weird space monsters. I also thought the Guardians were the coolest thing ever at the time, and the way they were built up in the story was really good. I'd love to revisit this game someday.
Also, yeah, the screenshots added are from The Ship, not RIM Battle planets.