Here is the full list of all 11 Firewerx achievements.
Launch your first firework!
Detonate a firework with a flashiness value greater than 20
Earn over $100,000 in Sandbox Mode
Successfully complete an order
Complete enough orders to reach Level 1!
Reach Level 5.
Reach Level 10.
Equip a firework skin in both slots.
Completely fill a Large Firework Shell.