In the code id Software sometimes there are unmatched pearls. The most famous is, of course, 0x5f3759df , which even got comics on xkcd . Here we are talking about filling the screen: pixels are colored one at a time in random order, without repetition. How is this done?
The first version of the game was written by Douglas Smith in 1982 in Fortran, he used the character graphics and it was called Kong.
What is funny, the creator has sent a demo version to Broderbund and the company rejected his offer of cooperation. Smith got the loan and reworked the game, and only after a second try he got the approval for the release of an improved program under the new name of Lode Runner.
Clones were many, for example: I started to play "Tarzan", but only in 1994 (!) Sierra has released a sequel, which was different from the usual game play, because there was possibility to play with another player and had a large number of traps.