Overview The game is very similar to The Legend of Zelda. The world is grid-based and shown from an overhead perspective. Progress is heavily based on tiered exploration, backtracking and searching every inch of the screen for secret entrances. In a somewhat mean move, Sega included bad NPCs that take horns (in-game currency) from you, essentially punishing you for finding the secret entrance in the first place. There are also a lot of RPG staples like hotels and traders, most of them hidden.
This game uses a battery for the saved games, something very uncommon for the Sega Master System. Outside of the villages, you have to find save points yourself which can be quite inconvenient. Since the entrances are not marked in any way, you have to memorize which one leads to a trader, a hotel and so forth. There are no signposts in this game, either. In turn, you will find yourself wandering around aimlessly quite a bit. As far as the villages themselves go, they are pretty sparse and usually only one screen large.
There are several dungeons in this game, too. They are conveniently numbered which is helpful if you accidentally wind up in a later dungeon like number IV, which is accessible right from the start. Exploration inside a dungeon is based on small keys, not unlike Zelda. There is a big treasure chest in every dungeon, and since they contain important items, you can't afford to miss any of them. There are also some switch puzzles, but nothing too fancy. Sega included another somewhat sadistic mechanic with a number of pushable chandeliers that can't be distinguished from the normal ones. Since there are at least two of them on every screen in a dungeon, you end up violently pushing innocent chandeliers in true trial-and-error fashion.
Most enemies in this game are color-coded, the basic version being green and fairly easy to beat. The blue versions often have special abilities like more powerful projectiles or the ability to multiply. The red ones are just nasty and should be avoided until clearing the first few dungeons. They are used to keep players from exploring too far. There is always the option to brute force your way through them, but sooner or later you will hit a dead end because you lack a certain item. All of this should be very familiar to Zelda players.
There is also a map, an inventory, a trading system, and a simple variation of "pick a card". You can buy small keys for the dungeons at the risk of potentially missing large parts of them. There are also some better armors, shields, and weapons in this game. The red armor can actually start to rust - a status that can be remedied with magic oil. Some items, like the Knight's Shield, are only available at certain traders once they are found.
The health is indicated by small hearts, the magic power by blue pitchers. The heart-meter can be enlarged by defeating bosses and finding or being given a heart (unlike Zelda, there are only full ones). Food is used to refill your health and is either dropped by enemies or can be bought from traders. The latter is the only way to get Golden Apples which will refill all your hearts once selected in the inventory and activated.
Another noteworthy aspect is the strangely high number of projectiles in this game. Seemingly everything can shoot, even ancient skulls in the desert. On some screens, this game turns into a regular RPG bullet hell with red balls flying at you from all sides, especially around coastlines.