assembled by Tabata based on their development experience with action games. While working inside the control and hardware limitations of the title, the team created firearms and the lock-on mechanic as the fundamental attack action, instead of the free-roaming style of a standard third-person shooter. While designing levels to function with the game's Overdive system, the team considered what the level would hold, how often players would utilize the function, the difficulty of levels, and the positioning and strength of enemies. During development, a questionnaire was circulated around company staff concerning the character Aya, to find out which of the planned features were popular. One of those that survived in the final game was Aya's clothes being damaged when she was hit by an enemy. Nomura was among the first to suggest this feature originally, tying it with increased enemy difficulty to present a dilemma to players who "might purposely make her take damage just to see more of her body". Nomura worked on the character designs for the main cast. He was originally only going to work on Aya and Eve, but after seeing the settings for the other characters, he offered to design them too. The team wanted to emphasize the character's sexuality. As part of this, the team included a scene where Aya takes a shower. This was inspired by a similar scene in Parasite Eve II. When the title was being developed for PSP, the team's main challenge with the character was to make her look as realistic as possible while retaining her established physical traits. Using this new realism, the team wanted to portray the fear felt by humans when faced with such threats through Aya. Achieving this realism proved one of the most difficult aspects of development. Her alternate costumes were not a high priority for the team, so their artists had high creative freedom. While many of the concepts for the final version were present in the original mobile version, such as Overdive and the Twisted, the original story was scrapped when the game came to upgraded platforms. In creating the story for The 3rd Birthday, the team took inspiration from the 10-year gap in the character's in-game and real-time history. This meant that it would be difficult to create a straightforward sequel, so the team instead decided to make the game about Aya's return. Toriyama imagined story concepts such as the snowy