Here is the full list of all 26 Söldner-X 2: Final Prototype (Physical) trophies - there are 14 bronze, 3 silver, 8 gold and 1 platinum.
Shoot down a rare enemy
Clear challenge 'Rating Expert'
Complete the fifth stage ('Turady Deep Sea') at any difficulty level
Complete the third stage ('Ethia Ruins') at any difficulty level
Complete the first stage ('Zeus Sector') at any difficulty level
Collect all other trophies
Complete the seventh stage ('Van Krist Labs') at any difficulty level
Clear challenge 'Survivor'
Clear challenge 'Collector'
Clear challenge 'Action Fan'
Clear challenge 'Chain Expert'
Clear challenge 'Profiler'
Collect an accumulated total of 77777 chain rings
Collect all 35 secret keys in stage one through seven
Unlock and successfully pass 12 or more challenges
Clear challenge 'Speed Gunner'
Clear challenge 'Stage Keys'
Clear challenge 'Speed Collector'
Clear challenge 'Rank Master'
Clear challenge 'Kill Collector 1'
Clear challenge 'Score Collector 1'
Clear challenge 'Hellfire'
Complete the tenth stage ('Inner Core') at any difficulty level
Defeat the final boss in stage eight in under 115 seconds
Unlock at least seven specials
Collect all 15 secret keys in stage eight through ten