Well it had its desired effect, the transformation scenes looked incredible at the time, and no one will forget the first time they heard their Mega Drive speak to them.
I had nostalgia for it, well until I went back to play it, it still has a charm though, there's some really weird character designs in that game and the co-op mode can still be fun.
The multitude of ports to other systems are pretty much universally horrible, if you were a Master System NES or C64 owner it really brought home the huge leap in power between the machines, just compare the screenshots.
Mega Drive:
Master System:
Famicom:
C64:
And for reference the arcade original:
The Mega Drive version was damn close, and though it lost the lovely scaling effects it did gain some paralax scrolling. Still, the leap from the 8 bit generation was more than clear and since that's all Altered Beast was really meant to demonstrate it was a major success.