How do you follow up Super Mario bros. 3? For many people it was the epitome of the series. It expanded on the classic Super Mario Bros. platforming formula by fleshing out Mario's universe, his special powers, and constantly adding new and inventive level designs that were as joyous as they were challenging.
In many ways Super Mario World imitates the very successful SMB3 formula, but it's misleading to assume that it just copies it outright and simply updates the game design graphically. In many ways SMW is everything that couldn't fit into SMB3 and more. It's a case of 'bigger and better' to put it very coarsely.
The first thing that strikes you when you begin is the size of the world map. Pressing the shoulder buttons allows you to pan the map, and the promise of a large world to explore teases you from afar. It feels much more cohesive and unified than SMB3's seemingly random tourist destinations.
The feeling of a world is not just limited to sight either. The designers have endeavored to flesh out a wholly interactive and object-based experience. When you begin, you're able to visit Yoshi's house, a new character back then, and read a text box offering background information on his possible whereabouts. So even before the game has begun, the situation and the ability to casually interact with the world is being established.
The levels of SMW have a similar feel to other Mario games. You have your horizontal platforms, your verticals, your diagonals. Mario's perilous momentum feels as tight as usual and the players' old 'shifting action' helps steady him. The traditional Goomba (low-level goon, simple mobile obstacle) has been replaced by some new goons, but the feeling is the same. Koopas form a large part of the enemy-level dynamic as usual, offering a surprisingly layered risk/opportunity spectrum. a simple jump on the head knocks them out, but they can still be kept in play if you jump on their shell. the way that this can either be useful or disastrous is a real Mario motif. These hallmarks are still intact. throughout SMW, platforms gain many amusing and enjoyable graphical disguises. there's always something new added.
Instead of the tourist destinations of separate worlds (desert, ice, lava etc.) in SMB3, Mario world appears to focus on the mushroom kingdom as the core theme. Mario finds himself in a weird parallel dimension of dinosaurs and mushrooms, bullets with angry faces, and spiky turtles. That's not to say every world looks the same, it's just that there is a return to the more standard grass-covered plains of the original Mario bros.
In many ways it feels like a melding of Zelda and Mario. You have your open plains melding into lakes, melding into caves, coming back up into open grassy plains, and then into a deep forest, and back out again into rocky terrain. The wider map is integrated into the levels.
Despite all the cohesive integration, Mario gameplay and design is still wonderfully abstract and nonchalant. The design of the space and its functions have come before the surface representations, graphical details and narrative. Level design is still chunky and geometric. Weird checkered patterns adorn backgrounds. Blocks with faces float in the air. Pipes stick out of the ground but lead to nowhere. Is this world organic, mechanical, soft, hard? the mario levels all feel distinct though, and memorable. caves feel cave-like. ghost houses feel ghostly, etc. the abstract design is part of the charming aesthetic, not a detraction.
The core of the game is its non-linear, playbox design. Mario has always been a fairly straightforward adventure. You move from the left to the right and work through the obstacles until finishing. SMB3 changed this approach by adding in a level warp system, where the player could find secret ways to bypass certain zones. SMW takes this idea of player awareness to important new levels. Each level has your standard 'get from point A to B' goal, but this in itself is not what makes the game compelling.
The designers have very carefully constructed many ways in which the player has options and divergences for play. The main way that they allow this is through the cape item. This was how Mario could become even more 'super' in SMB3, after growing like a mushroom. The 'p' (power) meter used the player's momentum to propel Mario into the air. As well as just being enjoyable in itself, it allowed the player to find hidden secrets such as coins and warp zones.
SMW streamlines the various special items and suits, and expands on the flying aspect, integrating it fully into the world. In doing so, the level designs are much more open and often larger in scope, with many hidden exits that lead to other places that wouldn't usually be accessible. The game confidently offers feathers to the player through floating item boxes or flying enemies. The player is left alone to experiment. The open design of the long horizontal and the visible skyline helps guide the player intuitively. Flying is an absolute joy. The mechanic has been tweaked to perfection. Not only can you glide but you can dip, bounce, and air bomb the ground. This mechanic is so nuanced that it feels like you're doing it all by yourself. The connection is very direct.
Due to the cape mechanic, play becomes free and chaotic rather like how sonic can bypass the carefully built platforms and landscapes to shoot across the sky like a pinball. There is such a beautiful tension between the convergent and divergent design. The player becomes aware of their power, and begins to tinker with the world that reacts in a realistic fashion. Testing pipes may or may not offer secrets. Getting the cape and then flying backwards to the beginning of the level may be done just for fun, or in the search for a new discovery. Using a Koopa shell to throw at item boxes may reveal a hidden plant that leads up to the sky. The design of the world offers so many surprises.
Another way that the game deepens the experience is via the switch palaces. Item blocks have always provided their function in the game, offering surprising powers or new ways to interact. but in SMW many levels have coloured invisible spaces. The discovery of coloured switch palaces enables these blocks in the levels, offering the chance to re-visit and re-discover familiar places. Considering that the switch palaces themselves are also hidden, it's like a very layered Easter egg hunt.
There are so many other ways that the world of Mario is deepened, and other ways that Mario can become super. Yoshi, Yoshi's individual powers, the star world, getting to Bowser's world early, hidden illusions in the ghost levels... and it all blends together masterfully.
My only criticism of SMW is that the game (and the music) isn't as uniquely iconic as the original, and some of the level designs aren't as enjoyable (the water levels, and forest levels). But otherwise, it's a scarily confident and inventive game design.