This is my first review, so please be gentle
I admit I was reluctant to pick this game up. I'd tried the online version a few years ago, and was not impressed. But when it went on sale on the Marketplace, I decided to give the demo a try. Using a controller instead of a mouse makes a HUGE difference. The premise is simple -- you are a fish. Eat fish smaller than you, and avoid fish bigger than you. As you eat, you grow, and can eat larger fish. You progress through 40 stages, until eventually you are able to eat the Shark King. There is something vaguely satisfying about being able to eat a type of fish that has killed you repeatedly.
A variety of powerups are available, including speed boosts, point multipliers, and ones that stun every fish on the screen and explode floating mines. The game is lenient with extra lives, giving you one every 6,000 points in addition to ones hidden inside clams on the seafloor or floating up in air bubbles. You also get two continues, however, unless you are going for the "Points Champion" achievement, you really don't need, them, as the game lets you continue from the last level you completed once you run out of lives and continues.
Unfortunately, I have encountered some technical glitches. On one occasion, my fish ceased being able to move vertically, so all I could do was move back and forth on the seafloor. When I finished the level, it went back to normal. More troubling is the fact that twice (so far), it has completely locked up my console, so I have had to shut it off (manually, as the guide button wouldn't work) and restart the console. I understand that glitches and "undocumented features" happen. However, this game isn't new, and it's completely unacceptable for the problems to have not been fixed by now.
As for the achievements, they are fairly balanced. Half of them are achieved just by finishing the game. The others encourage exploring the other game mode, Time Trial, and replaying the game. While a couple of these require at least a little skill, unfortunately some just require grinding, such as eating 1000 sharks, or the always classic "10 Hours."
The graphics are definitely cute, though nothing special, and the background music is inoffensive. Overall, it's fairly fun, though certainly not spectacular. I've found it to be a good game to play when I'm not feeling up to anything requiring actual effort or thought. I'd give it a B-, and say is worth picking up at 400 points.