Using heavy weapons tires you out a lot faster. Magic remains faithful to TES, while being further balanced. Spellmaking, enchanting, and alchemy all make a return. The main difference is that even if you get the ability to make your own spells or magic items, you can only use those effects that you have learned. So researching and learning new spells so you can learn their effects plays a big role.
Mages have to seek out knowledge just like a warrior seeks out weapons.
Well, it's completely new for one thing. It really bears no resemblance to the past engines. It's completely Direct3D, supports lighting, shadows, extreme poly counts, huge textures, skeletal animation. Our character system is very advanced. More on that later.