Its doing really well thanks.....nice of you to ask.
Content wise I'm on track, got pretty much all the points down I need to cover to get a beginner from 1st steps and cool retro 2D games, to creating a nice 3D world based shootem up on land,sea air, or space.
I'm mainly finding the organisation of the projects so that I can provide a very simple base version, then allow the reader to add content from the book, to be the hard and time consuming part.
The 1st couple of games are done and tidy, and hopefully quite recognizable
There's 6 others in more or less complete state but need to be set up so they provide that base level and add to it.. i really want people to type code, so I'm not going to provide complete source code on the support site.
The rest of the projects jump off from these basic concepts and then into 3D stuff which won't be quite so recognisable, though in my view pretty much every game follows the same principles of the original shoot-em-up, move, shoot, avoid...repeat. Only the complexity changes.
If I can find a nice simple way to maintain the code base I think I will be a lot faster to get more code done. That's the time killer at the moment. I am working with a code base which has to be very simple, and sometimes things need to be added to it as I'm explaining it in the code....so you step back...fix and continue... its surprisingly hard... But also start to be a lot of fun.