One of the the software engineering milestone is :
you can code any type of software, not only game , I mean , just using the if ..than statement
Why c++ or other sophisticated programming languages then ?
Just to make your life easier in case of large projects ( not to mention data protection or other feature of course..)
In conclusion
Can you make any kind of game in 3dgs ?
Yes
Is it easy to make a large project using c-script ?
No