Just a warning: the hard badge took me 2 and a half hours to beat. Make sure that you are prepared to take on the challenge. Hold the esc button to jump higher to avoid the spikes.
For those of you who have trouble with finding fish, here are the locations where I was able to find them: In Level 2, you can come across a place with a bunch of caves with a big boulder on the top left of the area, and you can find around 4 fish in the upper caves. At the start of level 3, there will be a small pond behind you where you can get 1 fish. In Level 4, you will likely come across an area with a waterfall; 2 fish can be found on the top of the area, a couple can be found in the cave inside the waterfall, and a bunch can be found in the water at the end of the caves. At any level, there can be a small opening under a small cliff with a bunch of brown plants around it where you can go left to find 2 fish. Fish will also be at the end of the challenge mode at any difficulty except easy. Note: the cave section in Level 2 can also be found in any level before Level 6. I hope this was helpful! :)
 "Lab of the Dead"){kind=icon}
 "Slush Invaders Game"){kind=icon}
 "Bullet Audyssey"){kind=icon}
 "Impasse"){kind=icon}
 "It's Just TIC TAC TOE"){kind=icon}
 "FireBlob"){kind=icon}
 "Get Off My Lawn"){kind=icon}
 "Insectonator"){kind=icon}
 "Lightbot 2.0"){kind=icon}
 "ESCAPE"){kind=icon}
 "Pixelo"){kind=icon}
 "Dino Run"){kind=icon}
 "Jelly Escape"){kind=icon}
 "Racing Comrade!"){kind=icon}
 "Proke"){kind=icon}
 "Run 3"){kind=icon}
 "Bush Whacker 2"){kind=icon}
 "Frog Fable"){kind=icon}
 "Don't Look Back"){kind=icon}