Opera (2in1)

Opera is a reconstruction of the level of the same name in vanilla Super Monkey Ball 2. It is the 25th Advanced stage. Opera is recognizable for being one of the most polarizing stages in the entirety of vanilla Super Monkey Ball 2: Either it's seen as pretty easy compared to many of the stages before it, or it's seen as one of the most agitating and frustrating levels in Expert. It's also recognizable for being one of the few vanilla SMB2 levels to appear in Touch and Roll (albeit it was split into two parts).

Description
The stage consists of four rings of stairs in a row, with each ring gradually getting steeper than the last one. The blue goal rests between the end of the third ring and top of the last ring, while the blue goal rests at the very bottom of the stage. The player starts at the top.

Goal tutorial
Choose a side, switching between rings if you wish, and gradually roll down the stage. For the first two sets of staircases, you can go at a moderate pace. The third set of staircases, however, is just steep enough that your ball will start bouncing more wildly and potentially fly off the stage if you go too fast, so you'll want to keep that in mind and adjust your speed accordingly. Once you make your way down this third set of staircases, turn towards the start of the stage to see a blue goal waiting for you.

If, however, you're looking to skip stages, then proceed down the final set of stairs. This set of staircases is twice as steep at the third one, which means that if you don't roll down this set of stairs as slowly and carefully as you can, you will lose control and not be able to survive. Likewise, you can't go too slowly because there's a time limit at play here. Find just the right speed to make it to this green goal on time without losing control, and if you make it, this will allow you to skip Giant Comb and Beehive.

Differences from vanilla
Firstly, the original Opera only has one goal and it's at the very bottom. In order to resolve the polarizing nature of the stage, the bottom goal was made a green and a new blue goal was put just before this final set of stairs. This made it a much better stage to put as Advanced 25 as most of the other stages with green goals were either too hard (Launchers/Chipped Pipes) or too easy (Tilt Bridges/Junction) to put in late Advanced, or didn't merit a 60 second timer (Free Fall). This makes Opera one of the few stages in 2in1 to have a warp goal that wasn't present in the original, with the others being Floaters, Coaster, Mad Shuffle, and Construction. Two of the platforms have been extended a few units forwards to support the starting position and blue goal, those being the top-most step and the step between the third and last set of stairs.

There is one more substantial difference, however. Those familiar with the first game's Underwater background may have noticed that there's three floats with bowls of underwater plant matter, all of which are connected by chains. One of these floats connects to the other two with long blue bars. In Opera, these bars, as well as some of the surrounding chains, actually have collision. The stage is placed in a specific way so that the middle of the stage is more or less in the middle of these two bars. What this means is that the player can easily drop and bounce onto the first bar because it's below the first and second rings. While there are a few other stages that have background collision, Opera stands out because not only can you bounce off of this bar and still get in either of the goals, but bouncing off of this bar at a specific angle actually gets faster goal times than the usual IL/RTA strats. The link below provides two examples of this stunt in action, one of which was a failed run that could've gotten the blue goal with a 55. The only other stage in 2in1 where background collision provides faster times is Catapult.