Sonic the Hedgehog 2 on the Master System is not at all like the Genesis version. Yes, it's a platformer as well, but the levels, bosses and almost everything else is completely different. This game also introduces vehicles, such as hanggliders and minecarts. Like the first Sonic on the Master System, it's a good game, but nowhere near as good as its console counterpart.
And if it is, does it really matter?
To be this good takes ages