[The first was an App Store sensation, but what of its sequel? Ethan Einhorn, Sega's associate creative director on Super Monkey Ball 2 spells out the processes that led to the creation of the second game in the series -- including all the major triumphs and mistakes.]

The original Super Monkey Ball on iPhone was the number one paid app at the launch of the App Store. Rolling Ai-Ai the monkey around in 3D tied perfectly with the tilt/accelerometer functionality of the iPhone; this new way to play allowed SEGA to re-invent a classic intellectual property. The first game continues to sell well, and is held up by enthusiast gamers as a worthy challenge to their skills.

An interesting moment as a producer on Super Monkey Ball came when three of our testers insisted that they preferred the iPhone game to earlier versions in the series, which used an analog stick for control.

I asked them how long it had taken them to get used to the new mechanics, and they all guessed about 45 minutes. It was great to hear that they loved the game, but the learning curve represented a big problem: when considering the needs of the broad audience the game was intended for, the ramp-up time was about 43 minutes too long.

Sure enough, we saw a significant split in audience response to the finished game, based on this issue. Very patient gamers tended to respond enthusiastically, while users looking for instant fun felt that the game bordered on the unplayable.

A large number of players found that they simply could not get past the seventh board in the game, because turning using tilt proved to be far too sensitive.

We updated the game to include an on-screen gauge that let players know when they were holding the device at the correct angle for play, and we added a tutorial, but we knew that more would have to be done to make this Super Monkey Ball truly accessible to the audience that was enjoying Peggle and Flight Control.

We knew we needed to rebuild from scratch, and we were given that opportunity with Super Monkey Ball 2.

In addition to streamlined controls, we wanted to make sure that Super Monkey Ball 2 delivered cute 3D characters (the first game used sprites), multi-player racing, and a selection of mini-games, all key components to the series' DNA on traditional consoles. As character-driven platforming went, we wanted this game to set a new high bar on iPhone.

What Went Right

1. Building time into the schedule to iterate on the core play mechanics.

We knew how important balanced controls were going to be for this sequel. If we weren't able to fix the first game's biggest flaw, the project would be considered a failure by all involved.

Making tilt control work properly in 3D is much harder than most people realize. Unlike a driving game, which uses only one axis (tilting left and right only), 3D tilt requires left, right, forward and backward movement simultaneously, and this can only be done well at a narrowly defined play angle.

Consider: playing Super Monkey Ball 2 at a 30 degree angle can be done comfortably, but if you hold the iPhone over your head (say, while lying in bed), 3D tilt will not register at all. Calibration options are often suggested to overcome this, but if you look at 3D tilt in games that offer such features, it's easy to "break" the games by maxing out the sensitivity sliders. When a player does this, the movable object on the screen (usually a ball) can't shift left and right anymore.

We felt it was best to settle on one playing angle, and then test the hell out of it. This, combined with looking very carefully at the motion control data from the Wii Super Monkey Ball game, helped us come up with a control scheme that's proven to be friendly to newcomers and experienced players alike. It took about five complete passes to lock this down, and it was important that we front-loaded our schedule with time to work on this.