Flyingmouse's Level Pack
Flyingmouse's Level Pack is a Keen 3 levelpack that contains 21 levels.
The variety of levels is huge, ranging from keycard puzzles, to black and white levels, to levels that must be completed while the Ankh is used, to simple and short levels, to very long levels. The worldmap is designed in a way where Keen find and complete Intellect Towers, which block access to the final level aboard a flying fortress.
A recent update added in new sounds/music from other DOS games, altered most of the non-menu text, and edited a few levels to reduce the overall difficulty/fix broken level design.
Spoiler warning! This shows the whole levels.