I actually participate, as we speak, in the development of a MMORPG, which uses its own hand crafted 3d game engine in c++ and Java. Although the project is in

I actually participate, as we speak, in the development of a MMORPG, which uses its own hand crafted 3d game engine in c++ and Java. Although the project is in c++/Java, it faces numerous challenges regarding performance, so I really really doubt that it can be done in a functional programming language.