I still don't have my own copy of Electroplankton, but it remains something I look up on eBay every so often. Now it'll be rereleased in parts on the DSiware store. Too bad I don't have a DSi either. Hopefully someday, Electroplankton will swim into my collection. Until then, maybe I'll find myself downloading it at some point.
Details not in Japanese can be found at http://www.andriasang.com/e/blog/2009/07/04/electroplankton_dsiware/