@vitinho444 - I also looked into the Allegro library a while ago. What caught me was the mass amount of 2D support it did have. After a while of faffing about, and I didn't know enough of programming a pc then, I couldn't get them both to work together. I recently learned that Allegro uses HDC's for it primitive drawing capabilities, whether they can be mixed with GDK is another thing, I do not know.
However, all the stuff DBPro has, ie it's plugins such as Matrix1, Advanced2D, etc, I have come to like whilst using DBPro to test various stuff. I've recently switched over to Pure GDK, which is a little fiddlier to setup in Visual Studio C++ than Dark GDK, but, and the big but, is it does give you access to all those plugins that you 'just cannot' access from Dark GDK.
I can now access Advanced2D, D3DFunc, Matrix1, BlitzTerrain, the lot...
I will say it again, it is "fiddly" to set up, but worth it if you have the patience...
Warning! May contain Nuts!