1. I think most challenges should be open to whatever language, framework or game engine.
2. If it is very specific regarding a game engine, it should be very well justified.
3. Even with a good justification, it should be remembered that not everyone will be willing to download a bunch of dependencies to get in the challenge. For example, I wouldn't be willing to install JDK or Mono.NET. IF you are going to make a challenge that requires a specific dependency, at least chose a very easy one to get. Lua and Love2D are examples of extremely easy dependencies to install, and very lightweight.
1 minute ago, MarcusAseth said:So yeah, I agree with you it depends on the challenge, what I was thinking was to not mix them in the same "Make X Game" challenge.
Agreed. "Make X Game" is clearly something focused on design and creative. No reason to mix.