Camo - near the area with a large bolt, sniper joe, and a yellow jumpy dude, there's a small gap that you can slide through that will take you to the area with a "M" medal.

Diamond - in a reflection area where there are platforms with one block spaces between each platform, at the end of the room where you would normally drop down to the next room there is a ladder that you can grab that will take you to the area your reflection is normally in, go back to the start of the room and use item1 to reach the ladder to find an area with another "M" medal

Blaze - in the area that has you sliding from point to point while flames are being turn on and off, before you jump down the hole to continue, jump over the hole and slide into the area to the left, you will get a "N" medal

Glacier - in the area with conveyor belts, a sniper Joe, and spikes in the water. Slide between a belt and a platform and fall into a gap between the spikes and find a "G" Medal

Thorn - when you fall down a pit that has two paths, take the lower path and get to the water area, travel till you find a drop with spikes and fall down it to find a "III" Medal

Areo - the area with a destructible wall, use the Camo Missile on the wall and follow the path to find an "A" Medal

Razor - the area after the three ladders there's a pit with a weapon energy capsule on the other side, get to it using item1 and use a Camo Missile to destroy a part of the top of the room and use item1 to get to the ladder to find the "E" Medal

Arach - In the area with the grass patches in the last patch there is a hidden ladder, climb down it to find an "A" Medal

Collecting all the Medals will reward you with the Ultra ability. this ability changes your regular shots into charge shots.