It looks like a hacked-in method of giving Q2 some of Q3's functionality, and not much else. That it allows Q3 maps and such to be used in Q2 was probably intentional, but legally, the only way you could use them is to own Q3 anyway, so what's the point? If you own Q3, download Generations and play with the Strogg class only.
But, if this kind of thing excites you, more power to you!