2nd printing features a the 1st edition blue cover with artwork by Jeff Dee. The noticeable difference between 1st and 2nd edition is "A Wilderness Adventure for Character Levels 3-7" is printed on one line, top of the front cover.

Information courtesy of The Acaeum: http://www.acaeum.com/ddindexes/modpages/x.html#ixzz2xZurnUSq