The first significant development decision you'll probably make with Nu is whether to create an ImSim project or an MMCC project. Which project you should use can sometimes be unclear. Our guidance is as such -

If you're building a turn-based game like -

1. a puzzle game (like, Tetris, Puyo Puyo, or Panel de Pon)
2. a JRPG or SRPG (like Dragon Quest, Chrono Trigger, Fire Emblem, or Final Fantasy Tactics)
3. a strategy game or creation simulator (like Civilization or Sim City)

...then consider using MMCC Game. MMCC will give you unparalleled precision and expressiveness in building these sorts of game. You can learn more about MMCC here.

For all other types of games (or when the choice appear ambiguous), consider using ImSim Game. ImSim has the most flexible semantics that will work well with any type of game. You can learn more about ImSime here.

Technically, you can make any type of game with either approach, but some types of game will better utilize the affordances of one approach or the other. Also, it may simply come down to personal preference. If you're an extremely systematic coder and hold precision and program reasoning in the highest regard, you might prefer MMCC in more cases. If you're an extremely pragmatic coder and just want to sling code as fast as possible and / or experimentally, you might prefer ImSim in more cases.

Finally, if you regret your choice later in the project, the two APIs are designed to make porting to one another extremely straight-forward. So don't fret too much before landing on one. Again, if you can't choose, just go with ImSim.

As you my notice, there's another decision to be made when choosing a new project type in Gaia; that is whether to use a Game template or an Empty template. The Game templates includes all the code and files for a Nu game with a fully articulated, multi-screen life-cycle. If you're ready to make a commercially releasable game title, it's recommended you use a Game template to get you started quickly and provide good examples of how to make your own additional screens and screen flow.

However, if you just want to play around with and quickly learn either of the APIs with a potential throwaway project, you can choose an Empty template. Alternatively, you can also choose an Empty template if you want complete and full control of the Nu Game Engine as defined by your exact needs and / or desires.