Actually, you don't need to use GM as it had difference method, at least you need to touch some codes. Alternatively, if you want visual script like Construct 2/3, you can use gameflow based on Unity. I successfull convert all of my games to unity using gameflow.
How exactly? Gameflow works like "if you do" then "do something". Very similar to C2/3. Another example, you want to give a button action? Just pick action "on click button..." Want to animate Sprite? Just pick action "play animation", and variable system like C2. That's all.
And I don't even interested on C3 as it doesn't have killer features, really, I mean it.