It took me a while to really figure out what I thought about this game. Its formula isn't really all that different from other similar shooters.
Arcadia is another dual stick style shooter which was released on Steam fairly recently for 5 bucks. Unlike Bullet Candy, Arcadia isn't wave based. The player is given a playing space to cruse around in (quite quickly) and small shapes cruse into the arena with the sole mission of colliding with the player. Two modes of play, Casual and Chaotic, are given.
This is definitely not a flawless title. In fact, while I was playing it, I had thought of a lot of negative things to say about it, but despite all that, I continued to play it. The game play in and of itself is really good. The big problem is that it's a high score based game with no local high score board. (or any high score board for that matter.) The only way to gauge your progress is the achievement system, which consists of high score milestones. Also, gamepad support was recently added but is faulty at best. That appears to be something they are still working on.
Still, Arcadia sits in my Steam collection, constantly getting played like a trusty arcade cabinet. In fact, the library thumbnail looks a lot like an arcade marquee. This game gets the "just one more game" feeling down REALLY well. In fact, I would say it does this better than most of the other Steam dual stick shooters. If you don't have a dual stick shooter, Bullet Candy might be a better place to start, but otherwise this is a decent game to own.