Windows 10 build 10074

Windows 10 build 10074 is the first officially released Insider Preview build of Windows 10, which was released to Windows Insiders on 29 April 2015.

Cortana

 * Start and Cortana are now more integrated.
 * New experiences in Cortana powered by Bing Instant Answers.

Music and Video Preview Apps

 * Full screen mode has been added to the Music app.
 * You can now download movies, TV shows and TV seasons with the Video Preview app on up to three devices.

Other

 * Closing an application in Tablet Mode takes you to the Start screen now.
 * Multi-tasking improvements - Alt, Task-View, Snap Assist.
 * Windows Store has been expanded to 41 more markets.
 * Windows Store now uses a blue tile instead of gray.
 * New system sounds have been introduced.
 * New flat icons have been introduced, which would make it into the RTM.

Hardware compatibilities
If installing on VMware make sure to change the compatibility to version 12.x, otherwise the build will show a blue screen error when attempting to boot, and disable all network drivers or the build will update the time via the internet, thus activating the time bomb.