Both the lens cap and the door to the SD and connector compartment are made of a floppy rubber that's annoyingly difficult to get back into the correct position. In fact, the floppy door is so silly that Pentax had to add a second cover for the SD slot.
The camera's control layout and interface uses typical conventions, although it's a bit jarring to see the word "play" spelled out rather than indicated by an iconic arrow. The interactive control panel is straightforward and easy to use.
The mode dial has the usual PASM, Bulb, scene program and auto modes, plus a dedicated movie mode and three-shot HDR mode. The green button defaults to program shift and the red to movie record, but they're both customizable. I do find the green button a bit out of the way; it's not easily operated with your thumb or forefinger.
You can find designer Marc Newson's signature on the bottom by the battery compartment. I'm a little confused as to why it's not on the front of the camera, given how Pentax is hyping the camera's designinista roots.
In order to be able to support K-mount lenses natively, the K-01 of necessity has a huge flange-back distance -- the distance between the lens mount and the sensor. That's why the camera is so big, and I suspect why the 40mm lens has fringing issues. (What you see in there is the shutter, not the sensor.)