After playing through the game, I can say it doesn't quite escape the shadow of Project Diva, but that's not really a bad thing. It is a solid game with a few of it's own unique twists and plenty of nods to the anime that K-ON! fans will enjoy.

The core gameplay of
Houkago Live! is the same as
Project Diva or just about any other music/rhythm game: press the correct button in time with the music while a flashy video plays in the background. Where
HL! stands out is it allows you to select which girl (and therefore which instrument) you will play. Similar to
Rock Band, that instrument will be mixed to the front with it's own unique note chart. I really appreciated the thought that went into making each instrument unique. The guitar parts only use two buttons but have more complex patterns and combinations to hit. Drums come out fast and relentless with different buttons representing different parts of your kit. Keyboards make use all of the face buttons since there's just more things to push on a keyboard. And in a nod to the fans, the bass primarily uses arrow keys instead of face buttons since, you know, Mio is a lefty.

Just about every other feature from
Diva makes an appearance in some way. As you would expect, there are plenty of hairstyles and outfits to unlock including many notable ones from the show (except the "Don't Say Lazy" Outfits WTF Sega!?) and I like that there's no point/money/shop system, everything is unlocked directly through gameplay. Help items that make the songs easier (or in some cases harder) return in the form of snacks you receive from the girls after a performance. Even the Edit mode that allows you to create your own videos returns, now called "Sing!". This is where the language can be a real barrier and to be honest I did not get very far with this feature. I do know that unlike
Diva you cannot use your own music in this mode, so aspiring AMV directors, you have been warned.
One feature that IS new in
HL! is Ad Hoc multiplayer. Sadly, I will probably never get to play this since I will never be in the same room with four other people that own a PSP and this game IF I WAS THOUGH we could each play as one of the girls and it would be probably be rad.

Of course the real star of any music game is the soundtrack, and this is really going to determine whether you should get this game or not. The soundtrack is all
K-ON! all the time. If you don't like the music from the anime then this isn't your game, but yeah, you know that already. I am a big fan of the music from the show, however I was a little disappointed that there is only 19 songs in the game. Granted, each song has 5 unique note charts with 2 difficulties, but even still you end up repeating songs a LOT. Further, all the songs are from Season 1 so if you were hoping to rock out to "No, Thank You" like I was you're going to be disappointed. I understand getting any Season 2 songs was highly unlikely since the game was already in development, but that doesn't mean I have to like it.
All that aside, just about every Season 1 era song you would expect is here, including the b-sides from the OP and ED as well as most of the Character Image Song series. Each song has it's own appropriate video and setting and I have to say even with the repetition I was still enjoying myself. The instruments were different enough from each other to keep things interesting, but again, that will greatly depend on how much you enjoy these songs.

It is also worth noting how the game re-creates the laid back vibe of
K-ON. Much like the anime, there is a lot of eating cake and general fooling around in between playing music. The girls' clubroom acts as a hub of sorts, and while browsing the main menu the girls (in what I can only describe as "nendoroid form") wander in and out and generally do adorable things. Again, similar to
Diva, you can give the girls snacks and gifts which will occasionally trigger a mini-cut scene, but it's much more natural and a lot less, well... creepy... than the Diva rooms' "voyeur-cam" angle. This is another area the language can be a barrier since the cut-scene events are obviously all in Japanese, but if you watch the show you can kind of get the gist of what's going on. None of this is essential nor does it intrude on the gameplay, it just creates an atmosphere that is right in line with the show.
So to sum it up for those that might be interested in this game: if you are a fan of
K-ON! and have a PSP definitely check this out, a lot of attention went in to making a good game that fits right in with the anime. If you are a fan of
Project Diva but not necessarily
K-ON!, it's worth looking into but the short song list makes it a tough recommendation. If you are just curious about these games and have never played them, I'd recommend checking out
Diva first for the wider variety. Overall though, nice job Sega, I look forward to the sequel.