Here is the full list of all 30 Baseball Stars 2 achievements.
Win a game
Eliminate a AI player with a catch
Eliminate a AI player playing pitcher
Playing pitcher, hit the batter
Perform 1 homerun
Win a game by 10 runs
Loose a game by 10 runs
Win 5 straight games
Win 15 straight games
Perform 10 homerun
Complete the easy league
Complete the hard league
Win 5 games
Win 10 games
Win 20 games
Win 50 games
In single player mode, eliminate 3 batters playing pitcher
Complete a game with a friend in easy mode
Complete a game with a friend in hard mode
Win the Easy league
Win the Hard league
Playing pitcher, hit 10 times the batter
End a game with 0 run
Win a game without giving runs to the opponent
Play with all team of the Easy league
Complete Easy league with each team
Play with all team of the Hard league
Complete Hard league with each team
In single player mode, perform 5 straight strikes (pitcher)
In single player mode, perform 10 straight strikes (pitcher)