If you were around when this game was being released, you bore witness to Nintendo's first nationwide, mega-marketing campaign. Nintendo Power was all about SMB2, and you couldn't go into any toy store or watch any TV show without seeing ads. This grew even further with Super Mario 3, so it's interesting to look back and think of what game promotion looked like back then, when Nintendo was still arguably an "upstart."
As far as gameplay, it really was unique among the era's platformers with its whole "pick stuff up" system. That alone made it really feel like a sequel, a fact that Howard Philips at Nintendo recognized when he pushed back on the original SMB2 as a USA release. Since Doki Doki Panic was an internal Nintendo game anyway, its Mario-like heritage works even with all the kooky ways they shoehorned Mario and pals into it--and the heroes' sprites were goddamned impressive (arguably better than SMB3).
As far as gameplay, it really was unique among the era's platformers with its whole "pick stuff up" system. That alone made it really feel like a sequel, a fact that Howard Philips at Nintendo recognized when he pushed back on the original SMB2 as a USA release. Since Doki Doki Panic was an internal Nintendo game anyway, its Mario-like heritage works even with all the kooky ways they shoehorned Mario and pals into it--and the heroes' sprites were goddamned impressive (arguably better than SMB3).