The game is a neat little maze shooter by Synapse - think Berzerk, but with a large predefined game world, which adds a sense of exploration to the twitch reflex madness. IBM picked it up for its PC Entertainment Family series, and it wound up on our turbo XT clone, one of the first games I ever played on it. For a first-generation PC title, it wasn't bad; there was just one tiny little snag: the keyboard controls were offensively and game-breakingly horrible.
See, you move your character using the arrow keys, pressing them to walk and releasing them to stop. So far so good, except that the latter part doesn't work very well: the game randomly fails to register the fact that you've just released a key, leaving your character waltzing happily towards the nearest wall. And since the walls in this game kill you on touch, that's kind of like a guy with a weak bladder and poor aim playing russian roulette with an electric fence.
Solution: use a joystick - miraculously, controlling Shamus turns into a silky smooth experience, and not at all like driving a pre-recall 2010 Toyota Lexus with a sticky gas pedal! We did have a joystick to go with that machine, but to me it was an unwieldy monstrosity, probably meant for flight sims and such, and (fortunately for my carpal tunnel) I never took a liking to it. To this day I'm mostly a keyboard guy, but now we have DOSBox, which lets you map joystick events to keys; so I can tell the game I'm using a joystick, and proceed to enjoy my new, non-brain damaged input routines - even though I'm really using the keyboard.
Now that we've found a way to play this game without excessive input device mutilation, let us move on to the maps.
Warning: spoilers ahead!
As mentioned above, the level layout in the IBM port turned out to be rather different from the Atari version, at least in levels 2 and 3. I've retained the Atari map's color terminology for keys and keyholes, even though they're all plain green on the PC, courtesy of CGA limitations: you can tell them apart by the number and location of prongs, but that doesn't make a very concise textual legend.
Wherever several room numbers share the same color, the corresponding key will be found in one of them at random -- the others will contain an extra life or "mystery" powerup instead.
So there you have it. I've only ever beaten it on Novice, never on Advanced, but if you feel like undertaking such a monumental task^H^H^H^Hwaste of time, now's your chance.
Novice playthrough (sped up 3x):
As you can see, the endgame text is somewhat less disappointing than that of the Atari version - they've actually bothered to instill some sense of accomplishment there, and if you squint real hard, it's sort of rewarding. Wonder what it says if you beat it in Advanced?