Short answers, pulled from the story.
The 2011 Tōhoku earthquake and tsunami disrupted development schedules and caused health issues among Capcom staff, forcing the team to repurpose unfinished assets into a standalone title. Producer Ryota Niitsuma and his team chose to release Ultimate Marvel vs. Capcom 3 as a separate game at a discounted retail price rather than abandon the work.
Ultimate Marvel vs. Capcom 3 features 48 playable characters, combining the original 36 from the base game with 12 new fighters. Among the newcomers were fan favorites like Jill Valentine and Shuma-Gorath, who had previously been released as downloadable content before being pulled from online stores in December 2013.
The X-Factor mechanic in Ultimate Marvel vs. Capcom 3 was adjusted to allow activation while characters were in the air, a significant departure from the ground-only restriction of the original. This system granted increased damage output, speed, and health regeneration for a limited time, fundamentally shifting the strategic depth of the game.
The front cover bore the work of Capcom illustrator Shinkiro, while the reverse side displayed the comic book style of Marvel Comics' Mark Brooks. Brooks' alternate cover featured all twelve of the game's new characters, printed on a single reversible cover for the entire first run of the game in North America.
The Ancient Warriors Costume Pack, which included Magneto, was delayed and eventually removed from the pack due to the character's alternate costume bearing similarities to the attire of King Juan Carlos I of Spain. This incident highlighted the delicate balance between creative freedom and real-world sensitivities in the gaming industry.
Sales of Ultimate Marvel vs. Capcom 3 reached 1.20 million units by March 2015. The game earned a nomination for Fighting Game of the Year at the 15th Annual Interactive Achievement Awards and received generally favorable reviews with scores of 80 out of 100 and 79 out of 100 from Metacritic for the PlayStation 3 and Xbox 360 versions respectively.