Geometry Wars: Galaxies was a good play in my opinion.
Although this version is much richer (more maps/enemies) than its predecessors, the gameplay on Wii can be frustrating. The ship movement via Nunchuk worked fine, but aiming with the Wii remote became tedious after a while. I do like the fine control it offers, but my arm tensed up so much during the thick action that it actually threw my aim off!
This game was a fun shooter and it's neat to level up your helper drone! In the end, the game felt pretty repetitive and I lost my drive to unlock the last few systems. I think I would have liked this game more if I was better at it.
This was my first experience with Geometry Wars and I would say that unless you are a dedicated fan of the series, you would be better off renting this game than purchasing it. Oh, and pick up a classic controller if you don't have one (it's supported and it's got TWO analog sticks!!). Your arm will thank you later!