You might remember the great Hanano Puzzle by the Japanese game developer Qrostar. There is a
thread about it on this forum.
The author is now developing a new puzzle game that looks familiar to those who remember Hanano, but this new game has different mechanics. It's currently in beta and there is only a Japanese language version. However, I think you can figure it out without being able to read any of the texts. Just remember how Hanano worked.
At least in the current version, there are only two things you can do and they are controlled by the left and right mouse buttons. I think the appropriate difficulty rating is 8 brains out of 10, and for fun it is 9 out of ten. I base this estimate on solving the twenty levels in the beta version. I heartily recommend this game.
There is only a Windows version.
http://qrostar.skr.jp/index.cgi?page=jelly&lang=en
List of released versions
January 2013: Version 0.700 with 20 levels.
February 2013: Version 0.950 with 40 levels and English translation.
February 2013: Versions 0.990 to 0.993 with minor changes, but no new levels.
March 2013: Version 1.000. The game is complete.
All versions after 0.950 has the same levels, so you don't necessarily have to upgrade. You should be able to copy the save directory from an earlier version to a later one if you do upgrade.
Extras
Below is a link to three extra levels Qrostar rejected from the game itself for not being of good enough quality. They are quite challenging, though.
To play them, you have to move the files from the zip file into the data directory and replace some of the official levels. Make a backup of the original levels first.
http://qrostar.skr.jp/data/jellyextra.zip
Thanks to brian_s for pointing out the extra levels.
[Last edited by Pekka at 03-04-2013 06:42 PM : latest update]