I am a specialist of lunar serie on every machine it appears and this one is very simple compared to what has been done. However it stays an original game with albert odyssey battle style (other lunar games don't use exactly the same visual battle, it's different).
If you really wish to buy one, the most logical choice is golden sun 2 if you already have golden sun 1. If not buy lunar. the best choice is to download both of course, but it's your birthday and i understand you wish to have some pleasure to spend money this day.