ベストハンター Best Hunter
Score over 30,000 points in one stage
You get points for every enemy defeated and item you pick up. The amount of points you are awarded is multiplied by your combo multiplier. You need to get 30,000 points in one stage to obtain this trophy. You can probably get this naturally by going quickly through a stage and picking up items and defeating enemies. If not it can easily be farmed as there is no time limit the stages must be completed in and enemies respawn. See video under Combo Master
ライフセーバー Life saver
Remaining number of players is 9
You must get to 9 extra lives for this trophy. You can increase the number of extra lives you have by picking up the purple G items. lives at the end of a level carry over and you start each stage with at least 2 extra lives even if you finished the last stage with less than 2. A good level to farm these is the Lab. Here there are 3 of these G pickups and you might even get lucky and have an enemy drop one. The Lab is also an easy level with an easy boss. See video below for the location of the G items.
無傷の勇者 Intact hero
Defeated a boss with no damage
You need to beat a boss without getting hit. Below is a video against the boss in the Lab level. Most of his attacks are easy to dodge. If he blinks out then he will charge so jump over him and if he flies up then he will drop eggs which you can shoot before they hatch. He has one other move that is more difficult to dodge but sometimes he will go the entire fight without using it The school boss is also another good choice and even the final boss if you use the method under Beck Master
Befriend 10 enemies in one stage
Ecolo's charge ability causes defeated enemies to fight for you. First hit an enemy with a charged shot then shoot at it and defeat it normally. This will cause it to float behind you and fight for you. YOu can only have 1 ally at a time and can dismiss it by shooting another charge shot. You can hit enemies with the released ally. Befriend 10 enemies in one stage for this trophy
コンボマスター Combo master
Reach combo multiplier of 1.5x
You will add .01 to your combo multiplier for each enemy you defeat and item you pick up. Your multiplier will only go down if you do not defeat an enemy or pick up an item within a certain amount of time. This window is actually rather large so building a big combo is not difficult. You will not lose your combo if you get hit which also makes this very easy. You should be able to just speed run through levels killing enemies and picking up items an get 1.5 in the combo multiplier. If not this can easily be farmed since the enemies will respawn. See video below.
Cleared all 9 stages with one character
This is gotten by clearing all 5 story stages as well as the 4 extra stages that can be accessed by choosing the warp option on the level select screen. These levels and bosses are a bit harder than in the story but aren't too bad. Choose what ever character you are most comfortable with. I prefered Gun Vault as her double jump made avoiding enemy attacks, especially bosses, easier for me. Also she only shoots 3 shot bursts as opposed to Ecolo who shots 5 but GV's shots do more damage an bosses gain immunity for a few moments after getting hit so sometimes you only get 1 shot to hit.