Hi Gardevoir_J, thanks for your kind word and for playing. ^^
To solve the stage, give birth while facing left on the floating platform, the birthed monster will climb around the platform and reach the gun from behind:
oh!! thanks for the reply! i'm very upset i didn't see this a few months ago >~<. you wouldnt believe how close i got to finishing hte level through other tactics xD i played that level for almost an hour straight but in the end i gave up. now i can play again!! <3 <3