A.R.'s Puzzle Levelpack
A.R.'s Puzzle Levelpack (also known as Unknown I's 1st Levelpack) is a pack of 9 custom Keen 1 levels, most of which involve mazes.
Some of the levels use the tiles in a interesting way. There is no pogo in the whole pack, even though some levels require the pogo in order to be completed, therefore the player must use C+T+Space cheat in order to get it. Level 15 is a major edit of the Second Ice Shrine from the original Keen 1. Some of the levels on the map lead to nonexistent areas, where Keen would get killed as he enters them, possibly indicating that the pack is not complete yet.
Spoiler warning! This shows the whole levels.