Flaose's Original Level Pack
Flaose's Original Level Pack (also known as Unknown II's 1st and 2nd levelpacks) contains only two custom Keen 1 levels, one of which is very small, while the other is very large in level dimensions.
The levels are the second of their kind to be released on the internet (the first being The Ice Factory). It is the first levelpack to modify the title screen. The map was altered to remove the Border Town level, but the levels that lead to non-existent areas aren't removed, possibly meaning that the levelpack is incomplete.
Spoiler warning! This shows the whole levels.