The shields drop, that puts down a big bubble shield for your team mates to regenerate health in, handy. (plusxp.com)
We can see in gameplay footage posted here that the lightning, fire and bubble shields from Sonic 3 feature, in addition to the standard issue vanilla one. (seganerds.com)
You can use bubble shields, tube pieces and shield doors to form a tunnel, or you may fly over the skull and drop a teleporter exit so you can teleport to it directly. (gamerankings.com)