Not that you can tell from this webcomic format, but this was a big ol' "full bleed" page in its original incarnation, with the art extending all the way to the edges of the printed page; alas, the impact of that larger-format image is impossible to convey as a webcomic page. (Oh, well.)
In an surprisingly successful attempt to capture the feel of classic engravings, the landscape of the gates of Hell was rendered via the simple trick of inking in all the "Hellish" line art below the Vorpal Sword conventionally, then inverting the artwork in Photoshop to a white-on-black image.