The Neon Vector Shooter tutorial is a good way to start.
About the guiNode, I see not problem using it, it works well for 2d, the Neon Shooter is a good example of it. But if you want diferent ways, just search here in the forum, I remember I saw once a large discussion about how to fix axis in Z to do 2d games.
About the sprites, take a look on the wiki effects, there is something there also.
Another tip, you will find others game codes samples in the internet, and there is one tests select application in the Jm3 root installation dir where you can run a lot of examples.