The other half of the page is an advert for an apparently-hard-to-find (read: they couldn't get it into many bookshops) Harrison Ford biography.
Both of which were published, of course, to coincide with the UK release of INDIANA JONES AND THE LAST CRUSADE.
And here is what the first issue of INDIANA JONES (bottom left) might have looked like, courtesy of the Spotlight page (successor to Bullpen Bulletins) from SPIDER-MAN 597 (15 August 1984). Also note the Spider-man cover mock-up for the upcoming British adventures. That went through some changes as well before the final version saw print (as issue 609, the third chapter of the four part adventure). "In or around issue 605" eventually became 607-610. But... we'll get to that.
And SPLASH, the new GREMLINS-centric comic, planned for November 1984, never appeared. Although another comic, from another publisher, with the same name... did.