Here is the full list of all 27 Pixel Gear trophies - there are 10 bronze, 9 silver, 7 gold and 1 platinum.
Achieve the S Grade or better for the first time
Use the Bat's Pumpkin to blast 4 or more enemies!
Use the Powder Keg to blast away 3 or more enemies
Complete the third stage without receiving any damage
Complete the second stage without receiving any damage
Complete the first stage without receiving any damage
Use the “HP-Ghost" while having only 1 Life left
Kill 1000 Ghosts in total in the game
Kill 200 enemies with a Submachine Gun in total
Perform a total of 100 headshots to the Witch
Achieve the B Grade or better for the first time
Achieve the A Grade or better for the first time
Kill 500 Ghosts in total in the game
Collect 200 Gold in total in the game
Perform a total of 100 headshots to the Knight
Hurt 10 or more Angels during one play
Perform a total of 100 headshots to the Frankstein Monster
Perform 30 Combos during one play
Perform a total of 100 headshots to the Skeleton Warrior
Deflect in total 30 enemy bullets in a row during one play
Kill 100 Ghosts in total in the game
Achieve the C Grade or better for the first time
Perform 100 Headshots in total in the game
Kill 60 or more Ghosts in a level
Unlock all the Gold, Silver and Bronze Trophies in the game
Achieve the SSS Grade for the first time
Achieve the SS Grade or better for the first time