Contestants from across the United Kingdom and Ireland competed in a series of rounds that tested their physical stamina and mental attributes. The title of the show is a reference to Superman's home planet Krypton, the title perceiving that the contestants had strong superhuman "powers" for taking part in the challenges they were set. The contestants, from 1986 onwards, all had their own corresponding colour, either red, green, yellow or blue. They wore their own clothes, apart from the Physical Ability round where the contestants wore track suits which were, in early series, red, burgundy, orange, green, black, light blue and dark blue. From 1986 onwards, the tracksuits were red, green, yellow and blue, and varied in design over the series that followed. The track suits changed to black with a coloured stripe from 1990 to 1993. For their own clothes, the contestants either wore a shirt/blouse, tie or a neckscarf of their corresponding colour. The points contestants earned through the game were not referred to as their score, but as their "Krypton Factor", e.g. "The winner, with a Krypton Factor of 46, is the legal secretary from Kent, Mike Berry". The 1987 series won the prestigious Premio Ondas - Spanish Television Award for Entertainment.
The show was revived for two series which aired in 2009 and 2010, presented by Ben Shephard.
The first series of the show was shown on Wednesdays; it was presented by Gordon Burns and didn't have a studio audience. It was then on Fridays for two years before arriving on Mondays in 1980. Up to and including the 1979 series, Gordon Burns would be seen stood next to the scoreboard before being given a desk to sit behind from 1980 onwards (he would be seen sat next to the scoreboard for the 1980 and 1981 series before taking his traditional place in front of the audience and facing the contestants for the series which followed). In the first few series, there were no groups and eight heats, the winner of each advancing to a semi-final. The top two of each semi-final qualified for the Grand Final.
From 1981 to 1985, each series had twelve heats, from which each winner along with the top four runners-up progressed to the four semi-finals, the winners of which competed in the Grand Final. In 1986 and in 1987, the series was divided into four groups (A, B, C, and D). Each group consisted of three heats, with the winner of each heat and the highest scoring runner up of the heats within a group making it to the group final. The winner of each group final would qualify for the grand final. From 1988 to 1995, the series had 13 episodes, and only had three groups (A, B, and C). The highest scoring runner-up from the group finals would then go through to the Grand Final.
In 2009 and 2010, each series has seven heats and the winners of which in addition to the highest runner-up of the heats would qualify for the two semi-finals, the winners of which in addition to the top two overall runners-up advancing to the Grand Final. The overall winner of the Grand Final would receive a bronze trophy and would traditionally be titled as Superperson of the Year. Unusually, and possibly uniquely for the time, until 1993 (like the BBC), the series had no advert break in the middle even though it was on ITV in a primetime 7pm slot. This explains why some of the elements (most notably, the time for the quiz) were shortened in later series.