Cassette 50

Cassette 50 (Galaxy 50 - 50 Excitantes Juegos in Spain) is a video game compilation created by Cascade Games Ltd in 1983. Its 50 games were almost always written in BASIC. 
It was advertised a lot in home computer magazines. It came with a free Timex digital calculator watch. 
The instructions say "the games will provide many hours of entertainment for all the family at a fraction of the cost of other computer games".
In an interview, Matthew Lewis said he wrote "Galaxy Defence" in 12 hours at the age of 14. He sent it after seeing a small, anonymous ad in a local newspaper, losing the game's copyright and getting £10. His father, Ernest, drew the graphics.
Games.
Only some games are on all platforms (e.g. "Star Trek" and "Maze Eater"). Some games are ports or clones of older or popular games (e.g. "Lunar Lander"). Some games are made by independent developers. Some games with the same name between platforms are a different game. Some games have problems that make them harder to play.
Acorn Electron / Commodore 64 / Dragon 32 / Oric-1 / Oric Atmos / ZX81.
"Exchange" and "The Force" are not in the Acorn Electron version, but are listed on the inlay. The Dragon 32 version was released again with some updated games. The C64 version of "Tunnel Escape" is named ""Escape or Bust" in-game.
BBC Micro.
The inlay names "Dice Thrower" "Do Your Sums"".
ZX Spectrum.
The number with the '#' symbol shows where the game is on the tape.
The booklet names 'Star Trek' 'Startrek' and 'Jet Mobile' 'Jetmobile'.
Reception.
The games are very bad. Cassette 50 inspired the yearly Crap Games Competitions (e.g. the comp.sys.sinclair Crap Games Competition and the C64 Crap Game Compo) and a now-defunct website that reviewed bad games.