It's a remake. Have a look at the
Greenlight page, there's an early trailer. The game will be in full 3D, feature two new classes (Paladin & Rogue) next to the Mage, a survival mode that will include bigger parts of Solomon Dark, and.. apparently basically everything is being redone. And it's going to be the very first official PC & Android (PC first I think) release of a Solomon game, apart from the Dark beta, of course
It all sounds really promising, espcially as Raptisoft's design philosophy is to make every class be unique. For example he is absolutely against a "holy bolt" for the Paladin which in reality is just a "blue fireball", so he's trying to only include stuff that's really different from the rest. That kind of design really shows in Solomon Dark.
There's absolutely no ETA, but at least it's clear that he will take all the time he needs to make it really as good as he wants it to be
Greenlighting it can't hurt, though!