sequence seen in the teaser was the opening scene for the game. He added that it was created by Nomura, who had "a real clear picture of [what] the starting sequence" should be, and that the text seen and heard was going to "be a real integral part of the story". As Nomura stopped working on Final Fantasy XV, focusing his attention on other projects, including Kingdom Hearts III. Nomura revealed that the game had switched to using Epic Games' Unreal Engine 4, due to a "variety of reasons", with the development team having the full support of Epic. In January 2015, Yasue revealed that working on HD 2.5 Remix simultaneously allowed the developers to learn all the best qualities from the series to aid in creating III. Additionally, he stated the Kingdom Hearts team was sharing knowledge with the Final Fantasy XV team to expand the game and get the most out of the PlayStation 4 and Xbox One. A gameplay trailer was released during the Kingdom Hearts Orchestra World Tour in Los Angeles in mid-June 2017. The possibility of a Nintendo Switch version of the game might be created, but wanted to focus on the development and promise of completing the PlayStation 4 and Xbox One versions was thought. Nomura noted the long development was due to internal Square Enix corporate decisions, such as changing to the Unreal Engine 4 about a year into the game's development, which led to "extensive delays" and "a bit of time that needed to be rewinded and started over", and "certain timing and resources challenges within Square Enix", despite submitting and getting approved a plan for when more personal resources would be needed on the project. Regarding downloadable content (DLC) for the game, Nomura stated that "nothing is set in stone" regarding it, but he told the development team to "be prepared to be able to accommodate for something like that. We can't develop a system where we're accommodating for downloadable content. So it's not confirming or denying either way, but just so that the development team will be prepared". He would later add that he wanted to have some sort of additional content for the game, but nothing in depth had been discussed. Nomura was open to potentially adding customizable accessories, as was able to be done in Kingdom Hearts 0.2: Birth by Sleep – A Fragmentary Passage with Aqua, as