Bryce 3D is very much a big inspiration on the style of the environments and it would be really cool to utilize it in this game, but legally speaking, getting the correct license to distribute assets made in Bryce in a commercial product (such as an interactive game) is kind of a pain in the butt (the original software was sold by MetaCreations to Corel to DAZ, so even getting info about how to do so is confusing since DAZ wants people to use it's latest products).
The other big issue is getting old of software to work with modern Unity and if that's even feasible in comparison to just using similar techniques in a different software like blender.
Basically, these are big hurdles that make using Bryce 3D less feasible. Hopefully one day I can figure it all out! :D