LightSprites describes itself as kind of like "It's a Small World" on crack, and this is actually a pretty accurate description.
The basic concept behind LightSprites is very simple: colored targets pop up, and at the top of the screen you have a slingshot, which you can use to sling one or more colored balls at the targets. (You can select the color of the balls using either a key or from a menu in the corner.) Usually, the targets pop up in groups of three or four, and usually all of the targets in a single group are the same color, but this isn't always the case. If you hit a target with a correctly colored ball, a little figure comes out and dances around happily. Alas, should you hit a target with an incorrectly colored ball, a little figure will come out and dance around for about a second before some kind of terrible fate befalls him. This happens quite frequently, since often you'll set up a nice shot for one target and then suddenly another target of a different color will pop up. In normal mode, you just have a fixed number of targets, while in challenge mode, successfully getting targets will increase your energy, which gradually decreases over time (and also with an incorrect target); if it runs out, you lose. In both cases, the number of possible colors for the targets increases as the game goes on.
The art and music is really the fun part of the game. The graphics are cute and fun to watch, and the music is nice and bouncy. The sound effects can be a little annoying, but they add a nice element to the game, too. Sadly, the game has the (common) flaw that it is much easier on slow computers. You wouldn't expect it to make that much of a difference, but it's actually a lot easier to react and line up your shot when things aren't going quite as quickly.
Overall, this is a cute little concept and a fun little game. In fact, it's one of those games which is just as much fun to play the wrong way (and watch your little people suffer various horrible fates) as the right way.