Here is the full list of all 50 Skybolt Zack achievements.
Destroy a total of 100 000 enemies
Clear all achievements
In Score Attack finish one segment with 2 000 000 or more points
In Superplay mode finish clear the game with 5 or less retries
Beat Kaz in hard route
Full A rank
Full S rank
Finish World 5
Clear all A stages
Get an S rank on a boss level
In Time Attack finish one segment in less than 45 minutes
Complete a world 5 level in less than 30 seconds
Beat Kaz for the first time
Clear all B stages
Clear all C stages
Finish world 4
Complete a world 4 level in less than 30 seconds
Complete a world 2 level in less than 30 seconds
Complete a world 3 level in less than 30 seconds
Finish a level by killing less than 5 enemies
Finish world 3
Reach 100 Combos
Get a D rank
Finish world 2
Get a cumulative total score of 10 000 000 points
Finish world 1
Destroy a total of 9001 enemies
Reach 100 Chains
Complete a world 1 level in less than 30 seconds
Watched the whole game introduction scene
Get a B rank
Pass through 200 breakable walls
Reach 5 health points
Finish tutorial 3
Destroy 50 grey enemies
Get a C rank
Finish tutorial 2
Get a Z rank
Get a cumulative total score of 1 000 000 points
Make a "Full Combo"
Get a "No land break" bonus 5 times
Destroy a total of 1000 enemies
Make 30 wall bounces
Get the "No Damage" bonus 5 times
Get a "No break" bonus 5 times
Get the "No Misstake" bonus 5 times
Get a S rank
Smash the highest door for the first time
Get a A rank
Finish tutorial 1