Here is the full list of all 38 Code51: Mecha Arena trophies - there are 23 bronze, 10 silver, 4 gold and 1 platinum.
Collect 150 weapon upgrades in multiplayer games.
When using Fortress in a multiplayer game, start the Power Shield in DANGER state.
Collect 75 repair kits in multiplayer games.
When using Ninja in a multiplayer game, destroy 2 enemies with your EMP Blast.
When using Loong in a multiplayer game, destroy 2 enemies in a row without touching any ground.
Win 6 multiplayer games in a row.
Destroy 100 enemies in multiplayer games.
Reach level 5.
In a multiplayer game, kill 10 enemies in a row.
Lost most scores in 3 multiplayer games in a row.
Win a multiplayer game, in which you miss less than 25% shoots.
Suffered from 3 DANGER states, yet still survived in a multiplayer game.
Complete a practice or multiplayer game.
In a multiplayer game, kill an enemy in DANGER state.
Complete the tutorial level.
Start a match.
Get all other trophies.
Use Charge ability to kill 15 enemies in multiplayer games.
Complete 100 multiplayer games.
Complete 300 multiplayer games.
Win 50 multiplayer games.
Get 500 scores in a multiplayer game.
Kill 20 enemies in a multiplayer game.
Lose 10 multiplayer games in a row.
Win a multiplayer game without picking up any item.
Take the most damages in 3 multiplayer games in a row.
Reach level 25.
Reach level 50.
Drive 9 different mechs in mutlplayer games.
Take 3,000,000 damage points in multiplayer games.
Survive a multiplayer game.
Destroy 1000 enemies in multiplayer games.
When using Hell Fire in a multiplayer game, destroy 2 enemies using Ammo Flood.
When using Eskimo in a multiplayer game, destroy an enemy with your homing missile, who is not revealed by the radar.
When using Hunter in a multiplayer game, destroy an enemy with your minion.
When using Raven in a multiplayer game, destroy 3 enemies with your TOW Missile.
When using Ranger in a multiplayer game, achieve 30 critical hits.
When using Flash Flare in a multiplayer game, collect 9 supplies without being destroyed.