Here is the full list of all 12 STANDBY achievements.
Your first record in Speedrun mode
Beat The Game
You opened all levels
Level 5-5, Record 8.0
Level 4-6, Record 8.1
Level 4-2, Record 8.0
Level 3-8, Record 8.1
Level 3-1, Record 3.7
Level 2-7, Record 9.5
Level 2-1, Record 2.6
Level 1-3, Record 1.95
Level 1-1, Record 1.7