Bandai Namco has announced that the PC/Steam version New Gundam Breaker will be delayed to a later date this summer. The publisher's EU and UK Twitter accounts simply mention that more time is needed to improve the quality of the port.
In order to achieve the best possible quality for the game on PC, extra development time is needed to achieve this.
New Gundam Breaker for PlayStation 4 is still set for release on June 22 in North America and Europe. You can find the most recent footage, screenshots, and Gunpla customization details here.