Cover is altered from original: backgrounds have been changed, the Watcher figure was moved and the FF figures were enlarged.
Thing image taken from an issue of Fantastic Four.
Medusa illustration by Barry Smith is likely an original printed for the first time in this issue.
Dr. Strange art taken from the tee-shirt, which in turn was an amalgamation of figures from Strange Tales # 127 and 129. Vignettes added from various issues of Strange Tales.