Excellent use of HDR IMHO.
I really don't like the over saturated, color shifted, overdone images a lot of people post in the name of HDR, but I think your images are a great example of what HDR images should look like.
Yes they need a bit more contrast and a (transform) perspective adjustment but the images mimic what I personally think HDR was meant to do.
Create a digital image that comes as close as possible to what you're eye (with it's incredible ability to see the details in shadows and highlights) can see, and make it look natural.
That's HDR to me.
Good job :thumbup: