Electroplankton isn't a game, but a unique music making experiement. Problem is that you can't save what you achieve.
The basis of the game is little creatures called Electroplankton. There are ten in total and each have their own little concept behind how you make the sound. There are some that involve touching, dragging, and even speaking to your DS. All of which are concepts that the DS has only really brought to light around the time of this game's release.
The best way to describe all of this is a collection of toys. You use the different things to make different tunes. This is all very well presented and indeed uses all of the DS's many capabilities. One of the games has a hint of a game of sorts in that if you make all the leaves light up, the flower blooms, however you need to position the leaves to exactly the right position. The one that gives the most fun involves speech. You can alter what you say in many different formats, which can make for some often amusing consequences.
In my eyes, there is something that could have been included for people who use this as a music creator, and that is a ability to save your work. Some people could argue that this is more of a toy than a music creator, so its a matter of opinion. I will say that for retail price that this game could have had one, so it could give you some sence of achievement.
This is a toy, a highly sophisticated toy, but a toy nonetheless. Its simple to use, much like a toy at childhood, but at the same time gives a charm only something like this could achieve. Its lack of saving may give people cause to complain, but again, matter of opinion. Rent by all means, but unless you get a kick out of playing with toys, then this may not be for you.