Here is the full list of all 34 Sora achievements.
Cleared stage 2
Unlocked the first weapon
Cleared stage 1
Cleared all achievements in Sora
Cleared stage 3
Cleared stage 4
Cleared stage 5
Cleared stage 6
Cleared stage 7
Cleared EXTRA stage
Cleared stage 1 with rank A or higher
Cleared stage 2 with rank A or higher
Cleared stage 3 with rank A or higher
Cleared stage 4 with rank A or higher
Cleared stage 5 with rank A or higher
Cleared stage 6 with rank A or higher
Cleared stage 7 with rank A or higher
Cleared EXTRA stage with rank A or higher
Defeated a boss on Special difficulty
Defeated three bosses on Special difficulty
Defeated five bosses on Special difficulty
Defeated the Guardian on Special difficulty
Unlocked 10 weapons
Unlocked all weapons
Cleared a stage with S rank
Defeated Alte without being spotted by the Search Light
Defeated Tsih while she's stealthed
Defeated Mira without being hit by rolling blades
Defeated the Operator after defeating 30 wisps
Defeated the Ultimate Weapon without being hit by reflected beams
Defeated the Breaker without being hit by bombs
Defeated the Breaker phase 2 after destroying all warheads
Defeated the Dancer without being hit
Defeated the Guardian in under 1 minute