The DOS version uses a tweaked 256x200 pixel graphics mode and some other graphics trickery in EGA. Many VGA (and later) cards do not support this properly causing the game to hang after the character selection screen. DOSBox (starting at version 0.73) includes proper EGA emulation that allow this game to run when configured with the "machine=ega" option.
Gauntlet was voted #64 in the Top 100 Games of All Time poll published by Game Informer Magazine (Issue 100, August 2001).
There is an interesting note in the documentation for PCjr users:
Note to Pcjr users: If you wish to run the program in 16-color mode, the line DEVICE=PCJRMEM.COM present in the config.sys file on your boot disk must be changed to read DEVICE=PCJRMEM.COM /C instead.
This gives a clue as to how to get other Tandy 1000 graphic-mode games running on a PCjr (ironic, since the Tandy is a clone of the PCjr).