I've only got input, sound and the resource manager left to do. I know that my input kernel is working, at least partially, because I've been using it when I was testing my other kernels. I'll give the input kernel a bit of testing tomorrow but I don't expect many problems. The sound also shouldn't be that much trouble. DMusic is a nice API and I've used it before so I should be able to fix any bugs that crop up.
Once they're done I have the biggest and most complicated system left to debug - the resource manager. It has the most space to go wrong, especially since I've never written one before. But once its finished the engine will be what I'd call a usable beta.
So hopefully three, maybe four, days and I'll be getting to work on my next game.