Here is the full list of all 22 STARWHAL achievements.
Hold a Zone for 45 consecutive seconds
Win a Versus Heart Throb match being the sole holder of the Heart
Taunt 25 times in a single match
Get your first platinum medal
Get your first gold medal
Get your first silver medal
Get your first bronze medal
Play the game!
Obtain 30 Bronze medals in challenge mode
Die 100 times in Challenge Mode
Die 1000 times in Challenge Mode
Obtain 20 Gold in all Challenges
Obtain 15 Platinum in all Challenges
Obtain 25 Silver medals
Obtain 32 Platinum medals
Accumulate 32,768 total points in Score Attack
Shatter 1000 blocks of Ice
Play 10,000 rounds of Versus
Play 1,000 rounds of Versus
Stab 1,000 hearts in Classic mode
Stab 10,000 hearts in Classic mode
Accumulate 2,000 total points in Score Attack