Congratulations, you have successfully acquired a copy of akeen (0.11), a Commander Keen 1-3 level editor specifically designed for Keen 1-3 mod projects.
Essentially akeen is a level editor that has exactly the commands and properties I wanted in a level editor. This editor was made accordingly, and it wasn't made for general public, but I decided to release it because it took some effort to code and because it's quite handy for level editing. Written in C and using SDL, compiled in Windows for 32-bit hardware (I think...), it ought to run without problems at least in the near future. I'm not giving away the source but I'll try to keep it to be able to compile this for newer/other platforms if need arises.
The editor has a graphical user interface that is controlled with a keyboard. There is no mouse support. This is to keep the editor close to the aesthetics of adurdin's old(ish) DOS KeenEdit because I like it best. But because I need to use DosBox to use it and updating its graphics is its own task, and it doesn't have some things I want/need, I made my own editor.
This editor allows user to set the zoom level -- if it's set to 1 graphics aren't zoomed at all, with 2 one pixel becomes two pixels (like in DosBox), with 3 a pixel becomes 3x3 pixels.
Whenever a new level is started it's initially size 20x13 in this editor. User doesn't see the borders, they're set automatically when the level is saved. (If you want to edit the borders, tough luck, use some other editor for that.) The level floats in blue space. If you move up enough times, you appear at the bottom of the level, and vice versa. Same for left and right. To resize level -- by adding rows and columns to it, go above the side you want to add to. Then press insert. The level should be extended now. To remove from it, similarly go outside the level area on the side you want to remove, and press q & delete. Level should have shrunken now.
arrows - move around in editor and dialogues
space - places current tile in level
return - opens tile menu
c - place default tile
v - copy tile under pointer to current tile
f - fill with current tile (may crash, use with caution)
s - opens sprite menu
a - place current sprite
left shift + a - remove (set to 0) the current sprite
left shift + v - copy sprite under pointer to current sprite
insert - increases level space
q + delete - decreases (deletes) level space
backspace - opens/closes output console
r - prints information about level to output console
i - press when pointer is where a bridge switch is...
o - press when pointer is where you want a bridge to start at, and the sprite value for the corresponding switch will be created and placed to the coordinates saved by 'i'
pageup - moves editor view up fast
pagedown - moves editor view down fast
left shift + pageup - moves editor view right fast
left shift + pagedown - moves editor view left fast
5 - save level
6 - load level
left shift + f9 - create new, empty level (can't remember if this works properly, I always quit the editor and start it again to get a fresh level)
When the editor starts, it reads or tries to file akeendef.txt
As you can see, this help file is not as good as it could be, sorry about that. It should have all keys listed but I'm not sure. Anyway, to run the editor, place it to your Keen project folder. Remember to copy there the editor's files akeengfx.bmp and akeendef.txt and SDL.dll and make sure your folder has the tileset your mod uses, for example 1TIL0000.bmp if you're making a Keen 1 mod.