Here is the full list of all 51 JumpJet Rex achievements.
Defeat the second boss
Destroy 100 robots
Retry a level 30 times
Defeat the first boss
Collect every coin in a level
Complete Boot Camp
Play the game instead of letting it go extinct in your backlog
Die 500 times
Get 3 stars on 30 levels
Cover a level in ash
Collect every coin in every level
Spend 100,000 gold in the shop
Spend 1,000,000 gold in the shop
Complete adventure mode on easy
Complete adventure mode on normal.
Buy 20 different heads for Rex
Buy 30 different skin colors for Rex
Buy 30 different jet stream colors for Rex
Buy 20 pairs of jumpboots for Rex
Defeat the third boss
Defeat the fourth boss
Collect all the hidden items
With a 4x combo collect a ruby
Complete the RageQuit Rex mode
Complete the SpeedRun mode and post a time to the leaderboard
Beat Adventure mode on normal, getting every star and hidden package, under 3 hours
Beat Ragequit Rex without losing any lives.
Beat Speedrun Mode in under 90 minutes.
Destroy 25 snowballs in Snowblind without dying
Use death to your advantage in Cold Front
Stun the patroller in p1ng 3 times in one run
Use the shortcut for a photo finish in Scrollway
Use your projectile to trigger 75% of the switches in Power Core
Destroy 100 fireseeds in Jungle Jump
Get a 5x bounce combo on the first boss
Defeat the Yeti using only snow chunks
Find Seedmours weak spot!
Get a 100pt combo on Rex's target practice machine in the Dinonaut Base.
Score 3 points in Holoball in the Rexercise Room
Beat a level in Co-op mode
Complete adventure mode in co-op
Master one level
Master all levels
Live to fly another day.
Pay the ultimate price.
Kill the Big Globowski in under 30 seconds
Have a 4x coin combo multiplier lasting over 30 seconds
Beat the target time for a level without using Jump
Beat the target time for a level without using Dash, Drop or Rocket
Beat P1ng in less than 10 seconds
Get 3 stars on all 4 bosses