I got invited to the Mythos closed beta earlier today and ive been playing it a bit, its like the real Diablo 2 clone, the skill trees are separated by tabs just like in diablo 2, it uses the same camera perspective (its 3D but can only be played in the isometric view, you can only zoom in and out), and it has dungeon runners like graphics (but better), there are also gamble merchants (like gheed) and some more stuff, also the first monsters i killed were blue fallens with their shaman (that revives them).
There are 3 races and 3 classes and each class with their 3 skill tabs and each tab has 3 or 4 skill trees (if i remember correctly).
Mythos webpage