This game. What you are looking at here is one of the few games in its era that accomplished style and flair in a 3d engine. While the quirks of the pivotal grappling movement requires some getting used to, overall you have a very accessible and fun shooter with elements of exploration, platforming, and puzzle solving that all culminate into some fairly memorable and very creative bossfights. Even the ways bosses may end up being reused is extremely fun, adapting to their obvious weaknesses and having more and more witty exchanges with the protagonists.
Also, if you can, grab a controller with a friend to burn through the campaign in co-op, or four controllers for what is possibly some of the silliest versus matches you can get, all owing to some of the creative repurposing of obstacles from the story missions into arenas.
Overall, insanely charming-- However, if there's anything more to consider, it's probably buying the game for that soundtrack alone. Every single song combines the original Bionic Commando's chiptune composition with Simon Viklund's RIDICULOUS skill in merged synth + analog instruments to create total bangers like "Heatwave" or pensive, minimalistic tracks like "Ok, We'll Move".
In the big picture, Rearmed may not be revolutionary, but throw in that artisan soundtrack and standout aesthetic, you'll not only get a fat hidden gem; you're getting a rare inspired miracle from Capcom you just won't ever forget.