Almost every kids' game that I've ever played suffers from the same delusion: because the target audience is young, you can give them crap and they won't mind. Thankfully,
The Amazing Virtual Sea-Monkeys has come along and shown that you don't have to make a game stupid to gear it to kids. Yes, this is more of a virtual experiment than it is a game, but there are challenges nonetheless, and they're the sort that kids will undoubtedly get a kick out of dealing with, especially young girls.
The concept of The Amazing Virtual Sea-Monkeys should be pretty much self-evident from the title. Instead of the brine shrimp that we have in the non-virtual world, the game sports computer versions of the family we've always seen on the advertisements and the cartoon. They're, admittedly, much cuter than brine shrimp, and they can certainly do more things. The 'game,' as it is, centers around you keeping them alive and happy, by a variety of methods.
For example, when you first empty the 'Instant Life' packet into the water, you'll find the tiny little Sea-Monkeys tooling around almost instantly. There are a number of clam shells around the part of the tank that you start in, and they get pearls inside of them. Sending the monkeys over to the pearls nets you points, which you can use to buy things to populate the tank with.
The things that you can buy are varied. You can get seaweed to oxygenate the water; you can get fish to tool around, look pretty, and even interact with each other; you can buy aerators, food, and even houses that the Sea-Monkeys can live in and, er, have babies in as well.
While the game starts you off in a small section of the tank, it will soon open up into a much larger arena. The Sea-Monkeys happily amble around in the tank, picking up pearls--using snails to attract them is key to getting the pearls--and just messing around. You can buy all sorts of crazy stuff, like karaoke machines and a ball to play water polo with, and the Sea-Monkeys interact with them.
Of course, each Sea-Monkey is different. They may like different things, different areas and so on. They also have a large number of attributes to deal with, from their health to the amount of pollutants in their system, their oxygen levels, and whether or not they are sick. They can get cold, hot, hungry, ill, and even die of old age. They can even mate, if there is somewhere private that they can go to . . . eh. It's a vastly simplified version of real life, but it's well-done nonetheless. This should come as no surprise--Creature Labs is the company who made the Creatures games.
If the game suffers, it's because of the necessary waiting time. Getting them to get the pearls, micromanaging them, waiting for them to grow up, waiting to get enough pearls to buy the interesting stuff--it can be somewhat frustrating. But kids will undoubtedly have fun just looking around, and if all of the Monkeys die off in the tank you can always get more, or start a new tank.