First there's the new terraced battery. These cells are custom shaped to fit the specific contours of the enclosure, resulting in 35 percent more battery cell capacity into the wedge-shaped aluminum shell than would have been possible before.
While this is a technological leap forward, it does mean that the batteries are much harder to replace thanks to the huge amounts of adhesive that has been used to hold them in place.
Then there's the new trackpad. Rather than the old, monolithic clunk action, this new one uses strain gauges so you can click anywhere on the trackpad. The new sensors can also detect how hard the user is pressing on the trackpad, a feature called Force Touch. Different actions can be carried out depending on what they are pressing on.
There's also a new haptic force-feedback that sends feedback to the user as they use the trackpad.
Then there's the new all-singing, all-dancing USB-C port, which replaces every other port found on a MacBook - including the MagSafe port. It can do a lot (although some functions require an adapter, which is sold separately):
USB 3.1 Gen 1 (up to 5 Gbps)
Native DisplayPort 1.2 video output
VGA output using USB-C VGA Multiport Adapter (sold separately)
HDMI video output using USB-C Digital AV Multiport Adapter (sold separately)
SK Hynix H9TKNNN4GDMRRR-NGM 4 Gb (512 MB) LPDDR3-SDRAM
Elpida/Micron J4216EFBG-GNL-F DDR3 SDRAM
Murata 339S0250 Wi-Fi Module
Texas Instruments TLC5951 PWM LED Driver
NXP PCAL6416A I/O Expander
Broadcom BCM5976 Touchscreen Controller
ST Microelectronics 32F103 ARM Cortex-M Based Microcontroller
Linear Technology LT3954 LED Converter
Also new is a redesigned mechanism underneath each key, with each key now also getting its own LED for backlighting, and a logic board that's 67 percent smaller than the one found inside the 11-inch MacBook Air.
Which brings us to reparability. It's not good. Not only are there handfuls of proprietary screws and gobs of adhesive to deal with, but there's a lot of delicate ribbon cabling to deal with, not to mention the fact that the connector for the single port the machine has is crammed under the display bracket. And to top it all off, the Retina display is a single unit, so if you break it, the price tag on a replacement is going to make you feel very sad.