From the introduction:
The goal of this book is to present to the player and judge the world of Gothic Earth in terms of Dungeons & Dragons (3.5 Edition). In creating this d20 System, there were two goals that guided the process. One goal was retaining the flavor of Masque of the Red Death. The other goal was accommodating the constraints and history of the Living Death Campaign. With the advent of Dungeons & Dragons (3.5 Edition) additional adjustments needed to be made. This update addresses Dungeons & Dragons (3.5 Edition), corrects some errors, and clarifies some rules.
Living Death, is an RPGA member-run tournament campaign. This campaign was already underway before the introduction of Dungeons & Dragons (3.5 Edition). That fact influenced some of the choices made during the design process. If you wish to use these rules for a home campaign, you may wish to make adjustments.
In general most aspects remain fairly similar to the original Masque of the Red Death. Magic is still slow, unreliable and occasionally dangerous to use. Gothic Earth is still set in the late 19th Century and the Classes, Skills and Feats have been adjusted to reflect that time period.