More radical than Sunshine’s chintzy cutscenes and horrific dialogue is its dedication to a single cohesive locale. You’d have to go back to Mario’s earliest 2-D adventures to find a game where the theme and aesthetic of every level is this static. Rather than fantastical, disparate worlds, à la Super Mario 64 or most other Mario games, Sunshine’s sandboxes are all locations around Isle Delfino—a harbor, an amusement park, a hotel, etc. Together, they build up the character of this tropical getaway, providing dimension and culture to the island while reinforcing the urgency of its people’s plight. The goop really is stinking up the joint from end to end, interrupting businesses and polluting waters. The singular personality of Isle Delfino even extends to the game’s music, where nearly every level’s soundtrack is built around Delfino Plaza’s exquisite theme. Outside the more narrative based Mario RPGs, you just don’t get to see that kind of broad world-building from the series.

But that consistency proves to be as much a problem as it is a boon. Without variation between stages, the game’s inherent repetition becomes worse. Producer Shigeru Miyamoto would later say the creative team only had a year and a half to build Sunshine, and it definitely feels like a victim of that abbreviated development. It has fewer worlds to explore than Mario 64, and most of its 120 collectible Shine Sprites come from repeated challenges and rote coin collection. When the game does get specific with its goals, like during the inventive boss fights or long vertiginous climbs, it feels like peak Mario and a logical evolution of what Mario 64 accomplished. Too often, though, it’s just bland platforming filler, the kind of repetitive missions that reek of rushed production.

Delfino Plaza, the small town-like hub that serves as your gateway to the rest of the island, is a testament to one of Sunshine’s undeniable additions to Mario 64: our hero’s expanded moveset. Much like the castle courtyard in its predecessor, the plaza acts as a playground and testbed for players to familiarize themselves with Mario’s many different jumps and moves. Whether it’s spraying water on the ground and sliding through to get a huge burst of speed as you coast down the docks on your belly or using a clever combination of Mario’s wall bouncing and spin jump to reach some distant place that should’ve been an impossibility, Sunshine builds on the surprising flexibility of its revolutionary predecessor in ways no future 3-D Mario game would. There’s a complexity and freedom to its controls that make bouncing around the plaza’s vaguely Mediterranean buildings as fun and tactilely rewarding as any of the actual missions hidden away in the game worlds and experimenting with how all those little moves fit together into longer chains of maneuvers is one of Sunshine’s greatest pleasures.

Then again, that complexity also breeds unwieldiness. Paired with a player-controlled camera that’s ill-suited to dealing with the tight spaces the game sometimes forces you into, all those options and combinations make getting around even harder than it’s supposed to be. Luckily, F.L.U.D.D. is there to act as a safety net, its hovering capabilities giving you the chance to mitigate the consequences of a bad jump or mispressed button. When you’re locked in and speeding Mario through some floating platformer gauntlet, the game plays like a dream, but it’s all too easy for your fingers to get tied up, leading to silly frustrating deaths.

The peculiarities that make Mario Sunshine the fascinating diversion it is today also stand as strikes against it and seemingly served as precautions for the 3-D Mario games that followed. For all the merits they deserve, the decisions to build up a single, well-defined setting and focus nearly every bit of the game’s design on F.L.U.D.D.’s limited capabilities led to horrific tedium. Mario Galaxy would correct course by returning to the themed, disconnected worlds of old and introducing a new creative philosophy that emphasized pithy interactions with tons of distinct mechanics so that no one idea overstays its welcome. The controls would be pared back and refined, making Mario’s moveset less robust but more manageable. And as fun as they are to watch out of context, Sunshine’s atypical foray into long, voiced cutscenes would also be excised as the series moved forward, with even the comparatively restrained Super Mario Galaxy proving to be too narrative heavy for Miyamoto.

With all the lessons Nintendo learned from Sunshine and the distance the company has kept from it in the last 15 years, it’ll be interesting to see the series return to this formula later this year in Super Mario Odyssey. Technology has come so far in the intervening years that the worlds Mario will be visiting can be so much larger and capable of defining themselves without any aesthetic overlapping. The big question is whether the game’s creators can avoid Sunshine’s biggest downfall and fill those outlandish spaces with all the fleet, impactful imagination that made the plumber’s last 10 years of 3-D outings so spectacular. At least we already know they stole some of Sunshine’s unbridled weirdness.