I didn't understand the topic well, is it about creating a game development environment or a development language? Does it allow the use of   eval() or exec()

Language. You are free to use anything to make that happen! 

But exec() makes everything easier and it would just become like Python, so what is required? Should we just modify and add to Python, or Developing a simple programming language from inception

I think the rules are vague on purpose. The challenge is essentially - surprise everybody, do what nobody else would do. Having specific guidelines would limit some creative approaches.