What is galactic alphabet?

Answer 1

The Standard Galactic Alphabet (SGA) is a writing system used throughout the Commander Keen series. It is a simple substitution cypher, where each letter in the Latin alphabet has been substituted with a different symbol. The SGA can be used to write in different languages; however, in the games the SGA is used to write messages in the English language only

There is some debate over the shape of some of the letters, such as the Z. In the reference translation above (which is remarkably similar to the translation found in Keen 3), it is shown as two vertical bars with a horizontal bar connecting them at the top. In Keen 6, the translation image is much smaller so each "bar" appears only one pixel wide/high. This gives the impression it should be a rounded shape, like an upside down U. However because of the increased resolution in the Keen 3 version, one could argue that it is not supposed to be rounded, otherwise it would contain curves like the letters N and O do (or even the top of the letter A.)

The SGA was created by Tom Hall. Originally for Keen 1 he drew some graphics for 'Exit' signs which he made look a bit more alien by changing the ordinary Latin letters a bit. After that he added other signs saying "hi" and "this is neat" (near Rayguns), and he ended up creating conversions for the other letters of the Latin alphabet in order for the signs to resemble writings in an alien language.