Here is the full list of all 15 Lethal League Blaze achievements.
Beat the arcade mode
Get a checkmark on every event in the story mode
Beat the story mode
Hit three players in a row
Rally the ball back and forth for at least ten times
Reach a ball speed of one thousand
Reach a ball speed of one million
Bunt the ball at 1000 speed or above
Play 100 matches
Play 500 matches
Play 1000 matches
Beat the arcade mode without using any continues
Beat the arcade mode with every character
Hit the ball back and forth in Lethal Volley for 16 times
Hit a goal in Strikers with a ball of at least 250 speed