Ready for the junkyard
Objective: Complete the first stage ('Zeus Sector') at any difficulty level
Piece of rock
Objective: Complete the third stage ('Ethia Ruins') at any difficulty level
Objective: Complete the fifth stage ('Turady Deep Sea') at any difficulty level
Objective: Clear challenge 'Survivor'
Objective: Clear challenge 'Collector'
Objective: Clear challenge 'Action Fan'
Objective: Clear challenge 'Chain Expert'
Objective: Clear challenge 'Profiler'
Objective: Clear challenge 'Rating Expert'
Lucky Number 7
Objective: Collect an accumulated total of 77777 chain rings
Objective: Collect all 35 secret keys
Objective: Unlock and successfully pass 12 or more challenges
Not that difficult after all (Bronze)
Objective: Complete the seventh stage ('Van Krist Labs') at any difficulty level
Can't hide from me (Silver)
Objective: Shoot down a rare enemy