Portion of a GamesRadar interview with Nicalis:

GR: What exactly is going to be different in Cave Story 3D?

Daisuke Amaya: The difference between the original Cave Story and Cave Story 3D is going to be the environments are going to be in full 3D, but we will keep the original style of the game, which is a 2D scrolling action game.

GR: So it’ll be 2D gameplay, but the character models and levels are now polygons?

Tyrone Rodriguez: Right, yeah. We’ve gone to a level of detail that probably is unheard of compared to what we did for the original WiiWare version. And now, as you said, you’ll see characters are fully 3D. The main character’s really cute – he’s got a scarf, he’s got this really great hat, and we’ve modeled him, along with the accompanying cast, as well as the enemies. The weapons are in full 3D, all the items, everything you see in the world has this level of depth that you’ll be able to really utilize with the 3DS’s stereoscopics

More of the interview here

More Details

– Published by Nippon Ichi
– developed by Nicalis
– due out this Summer
– remains side-scrolling
– features 3D effects
– retail release
– secrets and Easter eggs added

Link