Slightly worse than first Ouendan, this game is still amazingly enjoyable one. The songs aren't just THAT great I think.
When I first turned on my DS with Ouendan 2 cartridge in it, songs from the first game were already stuck in my head and I somehow knew that Ouendan 2 will be worse, the question was: will it be much worse or only slightly worse. I must say that after passing easy difficulty I was quite sad because I liked only a few out of 16 (+ 3 bonus, but not at that moment) songs, other I thought to be mediocre or sometimes even pure garbage (Pop Star is the best example). Luckily, just as with the first Ouendan, after playing the game for longer and unlocking higher difficulties I began to like more and more tracks. The songs are less catchy but more varied and more, I would say, rich in sounds.
In terms of the gameplay, almost nothing has changed, but changes are all for the better: we can skip the beginnings and endings of the songs now and we can see the song difficulty and our rank when we choose it. Also the difficulty is higher than in Ouendan (later songs on hard difficulty are much more challenging), which is good.
To sum it up, Moero! Nekketsu Rhythm Damashii: Osu! Tatakae! Ouendan 2 is a great rhythm game that's a bit less catchy than its predecessor but is also better in some areas. Add to it more songs and more challenge and you get a game that is just as addicting as the first one.