Joe

Setup:

Extract the DOSBox folder anywhere and the Joe folder to C:\
(If you'd rather do a proper installation of DOSBox, get the installer here: http://www.dosbox.com/download.php?main=1 )
(If you extracted the game elsewhere, change the DOSBox command later accordingly. Note that DOSBox doesn't like spaces in file paths.)
Run DOSBox.exe
Type in DOSBox prompt:

mount c C:\Joe
c:
joe


Start: Main menu (press enter or 1 to start game)
End: First 4 levels beaten
Continue system: Restart level on death


Game info:

Exit the screen to beat the level. Left and right arrow keys to walk. Up arrow to jump. R to restart level. K to show the number of keys you have. Esc to quit. All movement happens one action at a time; it's a puzzle game, not an action platformer.

Knowing the precise jump arc is key, and for your convenience I shall represent it here in glorious ASCII (# depicts ground, X your trajectory):

........
..XXXX..
.XX..XX.
.X....X.
########

If the next tile you'd travel to is solid, the jump ends and you fall straight down.