This week's Virtual Console release of Sonic 3D Blast is not the Sega Saturn version. It's the make-people-sad version. There are better ways to spend eight dollars to make yourself sad, and most of them don't feature an isometric perspective.
Sonic 3D Blast is barely a Sonic game, and plays nothing like the Sonic platformers previously seen on Virtual Console. It plays more like a bizarro sequel to Flicky, an obscure Sega arcade game from 1984. As in Flicky, Sonic's goal in Sonic 3D Blast is to find baby birds and take them to safety. It sounds far-fetched, but the link between both games is intentional, despite the fact that 3D Blast's hide-and-seek styled gameplay doesn't exactly jive with Sonic's usual emphasis on speed.
Sonic 3D Blast also features Flicky's loose controls and weird sense momentum, which, as you can guess, is super incredibly bad for a game that takes place in an isometric perspective. Sonic spends much of the game slip-sliding out of your control, careening into all sorts of deadly things while you try desperately to maintain control. The entire game plays like you've hit a patch of ice while driving. Do you turn into the slide, or away from the slide? In Sonic 3D Blast's case, either way will send you to a quick death.
Any good points? The music's nice. Some of it was later reused for Sonic Adventure, even. Otherwise, Sonic 3D Blast serves mainly to document the exact moment in time where the Sonic the Hedgehog series slipped from the early days of "Kind of fun until you get to Labyrinth Zone/Oil Ocean Zone/First Zone of Sonic 3" to the "This is entirely painful and I hate it" feeling you get from modern 3D Sonic games.
So no, you probably don't want to waste eight dollars on this thing. If you want to know what you're missing, look at the video below, and if you must play Sonic 3D Blast in some form, buy Sonic Mega Collection for the GameCube instead. It'll probably run you about eight dollars right now, and it includes a handful of actual good Sonic games as a bonus.