Record review is pretty basic - little more than a confirmation of the image you've just taken, with basic exposure information and (optionally) a histogram.
You can neither magnify nor delete an image in this mode.
The X1 has a choice of two screens in playback mode, either a simple display of the image with basic exposure information, or a more detailed view which can include a highlight clipping warning and RGB histogram. Unlike many modern compacts, you can't power up the X1 directly into play mode by pressing and holding the play button when the camera is switched off - you can only view your images when it's powered on with the lens extended.
This simple playback view just has the essential exposure information displayed below the image - shutter speed, aperture, and ISO.
This detailed display adds much more file and exposure information. It can include a clipping warning (with overexposed areas highlighted in red) and this tiny RGB histogram.
In play mode the the rear dial can be used to magnify the image in four steps. The third step appears to equate to 1:1 magnification, and going beyond this results in clear pixelation.
The four-way controller is used to navigate around the image, and the manual focus dial allows you to move between shots and compare them for sharpness.
Play Thumbnail Index
There's just one thumbnail display mode, a simple 4 x 4 grid. Both the four-way controller and the manual focus dial can be used to navigate through and select images for detailed viewing.
Deletion and Protection
Pressing the delete key brings up this mini-menu; you can choose to delete a single image or all on the card (which requires a second confirmation).
This screen shot also illustrates how unintuitive Leica's black 'highlighting' of the selected option can be when you've only got two options to choose from - it's far from obvious, at a glance, which item is selected.
Images may also be protected, however this is one of the very few functions that is only available by going into the main menu. Which is odd, as the WB and ISO buttons are unused in playback mode.