There are quite a few precedents for Ugh! First off, Ugh is a caveman - and we know there were a few of those about. Then there was the funny story of everyday cave life by an American radio comedian (Bob Newhart?) about how interesting a caveman's life was, living inside rocks, sitting on rocks, throwing rocks, eating rocks... Then CRL produced Caveman, which was all about stealinng pterodactyl eggs, then Softek brought Ugh! out on the Dragon. Ugh also goes about stealing eggs from a pterodactyl, only now he does it in colour on the Spectrum.
The screen layout is fairly simple. At the bottom left is Ugh's cave and at the top left is the pterodactyl's nest. Between the two locations a wide path zig-zags upwards. Another path makes lazier zig-zags over to the right and there are some dead ends leading off this configuration. Ugh must make his way from the cave up to the nest, steal an egg and return to his cave with it. Then he can go back for another egg. On his way up he is provided with a spear but has to abandon it to carry an egg. Fortunately life provides him with another once he returns to the cave and deposits an egg.
A spear is lost once it is thrown at one of the pot-bellied tyrannosaurus which shamble amiably along the paths in a random pattern. Once speared, the prehistoric reptilian retreats to the furthest edge of the screen before setting off again. Ugh' s other problem is the understandably distressed pterodactyl which flies above the terrain at the top of the screen, dropping - yes, you've got it - rocks. Bumping into a tyrannosaurus or getting hit by a rock causes instant death to Ugh, but he has three other relatives all called Ugh to take his place. With each screen cleared, there's a bit more to dodge.