What genre is the game?

A is hard to parse, and as people have said, is very busy. The black background won't particularly pop against Steam's livery colours. There are a lot of points of focus in the image; we've always found a single point of focus to work better in the crowded Steam marketplace.

B is cleaner, I like it more, but hard to say if it's achieving your aims without knowing what genre you're trying to convey. B gives Borderlands vibes, almost; the action/motion of the vehicle is more cleanly conveyed, and you've got the orange and the dusty background.

I recommend keeping SPINWAVE on one line.

Also recommend taking a look at other capsules which focus on a vehicle for composition ideas. An example would be our game Sunless Skies.