Bowser and his seven children have returned to stir up trouble for the Mario brothers. This time they have captured the Princess and enslaved the peaceful kingdom of Dinosaur Land. Join Mario, Luigi, and their new dinosaur pal, Yoshi, as they venture across Dinosaur Land's seven massive worlds, full of action-packed terrain.
Beta tester's stage
With a couple of Pro Action Replay (PAR) codes that walk Mario through unbeaten levels, one can access what appears to be a hidden beta testing stage. Trasher provides the directions:
Use AR code 7E0DD501. Start a new game, and walk to Yoshi's Island 2. Activate AR switch. Mario will automatically walk up to the Donut Ghost House and then get stuck between the ghost house and the area above it. Switch off AR, then beat the ghost house and save your game. Reset the game and enter the new code 7E0DD502. Open the same save slot and walk to Donut Plains 1. Switch on AR, and Mario will walk to the Donut Secret House. Turn off AR, then beat the secret ghost house via the secret exit (beat Big Boo). Save your game, and use the Star Road to get to Star World. Switch AR on. When Mario stops, move to the next dot and re-activate AR. Repeat until you walk to Star Road 5. Re-activate AR and you'll climb to the top of the hill. Switch AR off.
After that, all you have to do is press the A button at the top of the hill, and instead of heading onward to the Special World, you'll enter the test level! (My theory is that as long as you haven't found the secret exit in Star World 5, you can reach the test level without starting a new game. So if you have a save file where you haven't reached the Special World, just go as far you got in the Star World, then turn on the second PAR code and take it from there.)
The test level starts you out on a mushroom platform with a unique "No Yoshis" sign at the end, and Mario will walk over like he's entering a Fortress. The next screen is small stretch of land with the word "TEST" spelled out in Rotating Blocks above you. Head to the right, and a 1-Up Mushroom will pop out right before you see an arrow (also made with Rotating Blocks) pointing down the hole at the end of the level. Down the hole is the only place you can go, and it takes you back to the map screen.
It turns out that the programmers filled in all unused level sections with the same test level, so over 200 copies of the level exist in the game. For the curious, I've mapped out the entire test level. (Click image to enlarge.)
If you own ZSNES and the SMW ROM, you can play the stage yourself with this ZSNES save state. Just press A.
Map screen buddies
While messing around with a ZSNES save state, Calcwatch has uncovered an unused feature intended for the map screen: Lakitu and a blue jay! These guys were programmed into the game, but for reasons unknown were not included in the final product. Here's what they do: On the smaller map screens (i.e. the screen dedicated to Yoshi's Island) the blue jay flies back and forth under Mario, while on the large map screen (showing Donut Plains, Chocolate Island, etc.), Lakitu drops in and flies around Mario. These guys have no affect on the gameplay, however. Who knows what ideas Nintendo had in mind!
Calcwatch says: "If you want to reproduce the effect, open any SMW saved state with a hex editor and change the value at $19FB to $01 (which will add Lakitu) and the value at $19FC to $02 (which will add the blue jay)."
If you own ZSNES and the SMW ROM, you can see Lakitu and the blue jay in action with this altered ZSNES save state. Just walk out of Yoshi's House...