There are a few big difference between D&D and Ergeonite game characters. One difference is the way experience points are used. In D&D when a character hits a certain number of experience points, they "level up" and then can select some new skills or become more powerful in already existing skills. In the Ergeonite game, characters can spend experience points to buy up their skills at any time (so long as they have points to spend.
Another big difference is that there aren't classes in Ergeonite, so there is very little limitation on what any character can do. The only limitation so far, is that only half-elven characters can cast Mental-type spells. So, if you want a character who can fight with a gun, a sword, and cast spells, go for it!
Another difference is that in the Ergeonite Game, skills are the all-important thing, and those skills include the ability to make and even invent items. For instance, a character can take mining Ergeonite, refining Ergeonite, leather- working, and alteration spell-casting. Once that character has spent experience points to "level up" those skills, they can create leather armor, imbue the armor with Ergeonite and then cast a spell on the armor to give it a higher defense rating.
Which race you choose may effect your character's attributes scores, so be sure of what you ultimately want to concentrate on before you choose your race. Every race except humans must make "trades" to their attribute scores. See this Rules page for more detailed information.