Controlled in one of the earliest uses of the WASD keyboard layout, Beyond Dark Castle pits Prince Duncan, against the guards and bizarre minions of the Black Knight. Fresh off the previous year's Dark Castle, the Black Knight has moved up from throwing beer steins and instead wishes to challenge the player to hand to hand combat. The game was also developed by Jonathan Gay and Mark Pierce of Silicon Beach Studios, just one year after the original Dark Castle debuted.
The size and scope of the game are much greater than the original, with a less restrictive level hub and more elaborate levels. Where before it was limited to dungeons and caves in the first game, the Black Knight has apparently invested quite a bit of money into his castle tweaking the old locations and adding many new rooms. Especially bizarre is the computer room, which saves the game via giant levers and periodically sends out bolts of electricity that must be ducked under.
The main goal of the game is to outfit the main character with the shield and fireballs, find the five magic orbs scattered at the ends of every big level chain, and use them to unlock the Black Knight's final chamber. Gameplay hasn't changed much - Prince Duncan still runs, ducks, climbs, jumps, and throws rocks, although he can now wield maces and shovels to use in duels and fly a ramshackle helicopter pack across the lengthy forest and swamp levels. There are also bombs, which have a timed fused before exploding upwards and sideways, destroying brick walls, any enemy caught in its blast, and possibly even Prince Duncan himself.
Platforming segments are still the focus of the game. Many of the moving platforms are small, move quickly, and are at higher or lower elevations, which requires to be extremely careful with the jumps. Also carried over is the penalty for missing a jump, as instead of death, the player is whisked down a series of chutes into the dungeon where a key needs to be grabbed and making the way back to the level hub to start all over again. Similar to other games of its era Beyond Dark Castle is rarely forgiving.
The main title screen depicts a castle parapet, with two guards slowly walking back and forth. Dark Castle used a clip of Bach's Toccata & Fugue in D Minor for its title; Beyond Dark Castle uses a clip from a later section of the same song, punctuated with blasts of thunder and lightning.
The levels are divided up into four main sections - the west tower, the east tower, clock tower, and the basement. Other than the clock tower, each section houses a single orb, and each of the towers also unlocks an ability - shield in the west tower and fireballs in the east. Neither of these skills are required to beat the game, but they will make it easier in many spots.
The middle of each tower is occupied by a randomly generated labyrinth, one of the first scrolling levels found in a Dark Castle game. They're essentially a basic maze, made more difficult by the placement (or absence) of ropes to climb up or down levels, and in some spots there are spawn points to let snakes or rats drop down the ropes. Thankfully, these ropes come in clusters of three and are free to move back and forth between them in order to dodge falling enemies. The labyrinth is also timed in a way, as the player's health will steadily drop. The choice is making it to the end before it drops completely, or picking up potions along the way. There are also a great deal of bombs and fuel for the helicopter found in both labyrinths, so detouring a little bit can help later on.
The computer room found in the lower left side of the antechamber is full of switches to save the game. Proceeding upwards will be the clock tower, which has two exits - the left goes to the swamp, and the right goes to the forest. Each level is a lengthy scrolling affair with Prince Duncan manning a small helipack and throwing rocks in a bizarre medieval take on a space shooter. Vultures will fly along in space invaders cluster formations, mutants will yammer and throw rocks from below, and occasionally large birds or gargoyles will soar in directly at the player with the goal of knocking the pack clear from the player's pack. Near the end of each level is a floating eye, which follows similar shooter boss patterns and shooting rocks out at various angles. Beyond it should be the helipack, knock out a guard, and take the orb at the end.
The basement is easiest to access by running into the west tower base and falling into the pit, although there is the more refined way down too. Its dungeon is an updated take on Dark Castle's dungeon, with a torturer whipping a group of three prisoners - knock him out from behind and the prisoners will nod or shake their heads when under a group of keys. Take the wrong set and get crushed by a 16 ton weight. The other variation on the original dungeon is the inclusion of five doors, with one of them is randomly chosen as the correct exit (the others simply break the key). Once out of there, the catacombs house the final orb with the only obstacles being brick walls (picking up a lot of bombs in the labyrinth will make this much easier), snakes, and a floating eye that spits fireballs.
After obtaining and placing all five orbs the Black Knight's chamber is a relatively straightforward upwards affair with a duel to the death at the top.
Most of the enemies in Beyond Dark Castle are holdovers from the first game. The simple rat returns, and along with the addition of the snake marks the only enemy that won't kill the player if touched. Rats and snakes will both descend ropes if possible, although rats move at a much quicker pace as snakes tend to coil around and around the rope, thankfully giving more time to spot and dodge them (or peg them with a rock from afar).
The yammering rock throwing one eyed mutants also return, taunting the player, smacking their bottom in their direction, and lobbing rocks while cackling with glee and dancing around. The birds or vultures are back as well, hovering in a single spot before screeching and swooping down or sideways. They're one of the few enemies that is completely pattern based and easy to avoid.
Guards are also back. They still wander back and forth on their set path and if they turn towards the player while on the same level will immediately let loose with a lethal crossbow bolt. Rocks will knock them out for about ten seconds, giving time to run past, but fireballs will down them for good (or at least until the player re-enter that area and they respawn).
There are new guards, too - beefier, lazier ones. They calmly sit in a chair until the players approachs them, and then yank out a mace or shovel to battle them in a duel. The duels are relatively simple and only involve blocking their strikes and returning the strikes back, and after a few of those they'll groan and slump to the ground. The only one who isn't lazy is the brewer, who casually tosses his endless supply of mead in barrels down at the player in a bizarre blend of conveyor belts and Donkey Kong-esque barrel dodging.