A princess is attacked by the demon Varalys, who breaks her into three fairies and scatters them through the land. One of her kingdom's bravest knights, Jim, sets out to retrieve the fairies and the crystals that will restore her to her original form and allow him to slay Varalys.
While the original microcomputer versions sold well in Japan, the NES port later gained notoriety in North America for being terribly outdated in comparison to later, more refined, superior action RPG titles like The Legend of Zelda and Ys... some of which beat the '89 release to Anglophone shores. Compared to those later games, the graphics in Hydlide looked "messy and hard to interpret" in comparison. Unaware of when Hydlide first came out, some North Americans even wrongly accused Hydlide of being "a badly designed ripoff" of either The Legend of Zelda or Ys, when in reality, it was actually the other way around: both The Legend of Zelda or Ys were heavily influenced by Hydlide in the first place. This makes Hydlide a classic example of the "Seinfeld" Is Unfunny trope, with later generations failing to realize just how revolutionary it was for its time.
The game received several sequels, including Hydlide II for the PC-8801 and MSX in 1985, Super Hydlide (Hydlide 3 in Japan) for the MSX and PC-8801 computers in 1987 and Sega Mega Drive/Sega Genesis console in 1989. It was also remade as Virtual Hydlide for the Sega Saturn in 1995. While Hydlide II and Super Hydlide, with innovations such as a Morality Meter and Day Night Cycle, were considered good games in Japan, they became very outdated by the time Super Hydlide released in North America in 1990.
For clarity purposes, the original (or the Famicom/NES version) will be just called Hydlide, Hydlide II as Hydlide II, and Super Hydlide as Super.
This game contains examples of:
- Action RPG: This was one of the first ever games in the Action RPG genre, along with Dragon Slayer.
- Aerith and Bob: In a world containing the likes of Varalys and Kaizack, our hero is simply named Jim.
- Apocalyptic Log: When you board the spaceship in Super, you find a log from its crew detailing their slow transformation into mindless monsters at the hands of Kaizack.
- A Winner Is You: When you beat the game, you get a text "Congratulations!" While the player and the princess (you saved) just stand there doing their Idle animations, it then goes to the title screen.
- Big Bad: Varalys, the final boss of the original. He's reduced to the Dragon in Hydlide II and Super, with a dark crystal in the latter and Kaizack in the latter taking the role of Big Bad.
- Genre Shift: Super takes a hard left turn into science fiction around the halfway point.
- Guide Dang It!: There is absolutely no clue at any point what you're supposed to do.
- Joke Item: The Sega Pack in Super Hydlide. It even says "It's a joke." when you try to use it.
- Knight in Shining Armor: Jim.
- Mind Screw: Super goes all the way in the second half of the game, where you're in space fighting robots and finding computer data, not to mention the final battle where it's revealed that the game's Big Bad is in the fact the creator of the entire universe!
- Money Spider: Played straight in Super.
- Morality Meter: Hydlide II was one of the first ever games to feature this mechanic. The game introduced a morality meter where the player can be aligned with Justice, Normal, or Evil. Killing humans or good monsters lowers the player's morality, while fighting evil monsters increases it. If the player has an evil alignment, the townsfolk will ignore the player, denying access to certain clues, dialogues, equipment, and training.
- Rainbow Speak: The intros for the first two games.
- Regenerating Health: The original Hydlide was an Ur-Example of this trope. It introduced a health regeneration mechanic where health and magic slowly regenerate when standing still. It inspired the regenerating health mechanic in the more popular Ys series, decades before the mechanic eventually appeared in First-Person Shooter games with Halo.
- Wide-Open Sandbox: This was the Ur-Example of a fully-scaled open world. Unlike earlier role-playing games that used The Overworld concept, the open world of Hydlide was entirely to scale, fully traversable on foot. This would later become a hallmark of The Legend of Zelda.
- Wizard Needs Food Badly: You must eat, and eat regularly, to survive in Hydlide II and Super. Hydlide II was, in fact, one of the first games to feature this mechanic, after Panorama Toh.