It's actually an archive inside an archive so just extract the first part with WinRar and you should get a working .iso or .gcm file.
If Winrar extract the archive without errors the ISO is fine.
The error is Dolphin related (unsupported function). [more info: http://wiki.dolphin-emu.org/index.ph..._2:_Pets_(GC)]
It won't work (for now), wait new emu releases, or play something else.
That game is also available on other consoles and PC, so you can try those.
ある朝、気がついたんだ
僕はこの世界が嫌いなんだって