'The Japanese arcade hit Ikaruga receives the full Xbox Live Arcade treatment and is poised to launch on the platform this Wednesday, April 9, 2008 at 9:00 a.m. GMT (1:00 a.m. PDT)'
If you don't know what to do now, you obviously have no taste.
As for the achievements:
Target: Eboshidori
Destroy Eboshidori! 10
Target: Buppousou
Destroy Buppousou! 10
Target: Uzura
Destroy Uzura! 15
Target: Misago
Destroy Misago! 15
Target: Tageri
Destroy Tageri! 15
Good grade
Complete Chapter 1 in any mode with a grade of A or better 20
Fine Grade
Complete Chapter 2 in any mode with a grade of A or better 20
Excellent grade
Complete Chapter 3 in any mode with a grade of A or better 20
Stellar grade
Complete Chapter 4 in any mode with a grade of A or better 20
Star player
Complete the Final Chapter in any mode with a grade of A or better 20
Unstoppable
Clear the game in any mode without using Continue 25
Dot Eater
Clear a certain chapter in any mode without shooting at all 10
Unstoppable... tricky.