I think the only real kind of game C2 would struggle with would be "non-WYSIWYG" gameplay.
For example, and to illustrate what I mean, a dungeon crawler. Not a rogue-like, but an old-style fake-3D dungeon crawler (Dungeon Master, Black Crypt, Anvil of Dawn, etc.)
Graphics resources are only 2D sprites, the environment and the movement are tile-based, etc. but the problem comes from the fact that what the user sees is not what you edit when you create the game.
The entire level design is a 2D top-down maze, but that's not how you play the game. All the data and game logic is handled in memory, and what is presented to the user is just a different representation of the world.
This can be programmed very easily, but tools like C2 are designed to let you play what you design. I'm not saying creating a dungeon crawler with C2 is not possible, but it would be clunky and sub-optimal in terms of productivity.
That applies to every genre that relies heavily on data management behind the scene. Everything else should be a good candidate for C2 or similar tools.