I took another shot at it, since you mentioned changes. Room 2 seems better, but when I beat Room 4, I got this error:
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FATAL ERROR in Vertex Shader compilation
ShaderName: shd_distortion
D3DXCompile failed - result
at gml_Object_obj_trippy_background_Draw_0
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stack frame is
gml_Object_obj_trippy_background_Draw_0 (line -1)
Edit:
Oh, I guess I should also mention the other issues I had: Room 4's key is really hard to read, and for Room 3 I couldn't figure out what meaning of "overflow" would apply, since the normal programming meaning would just result in dropping digits. I also had to use this autohotkey script to figure out the morse code since I have no training.