The GF1 is essentially a G1 in a smaller package (without the viewfinder and articulated screen, obviously) so there's not a lot new here. That said, the mirrorless interchangeable lens digital camera is still such a novel concept that it's worth quickly running through the key features.
The GF1 has the same 12 megapixel (effective) Four Thirds format CMOS sensor with SSWF dust reduction system as the G1 (it certainly doesn't have the new multi aspect ratio version used in the GH1). As there is no mirror and the camera works in live view mode full time, the GF1 features a newly-designed focal plane shutter that stays open when powered down (conventional shutters are closed when powered down).
The new smaller lens mount and reduced flange back distance means that Micro Four Thirds lenses are noticeably smaller than their conventional SLR counterparts - even the already diminutive 14-42mm Olympus kit lens.
The GF1 ships with a new kit lens, the much anticipated 20mm F1.7 ASPH 'pancake'. A mere 23mm deep (excluding mount), the new lens makes for a camera that's just as pocketable as larger compacts (such as the Canon G10 and Sigma DP2).
Despite being almost exactly the same size as the Olympus E-P1, Panasonic has managed to squeeze a small pop-up flash into the GF1 using an ingenious (and rather complex) mechanism that lifts part of the top plate.
The GF1 trumps the G1 upon which it is based by adding HD movie recording. You can shoot in AVCHD Lite or M-JPEG modes. It's not quite up to GH1 standards (topping out at 720p), but it's a lot better than the G1.
In order to keep the size down Panasonic dropped the articulated screen on the GF1, but the spec remains the same; 3.0", 460,000 dots, wide viewing angle.
Panasonic offers an optional tilting electronic viewfinder, the LVF1, with the GF1.
New Venus Engine HD processor.
Exposure meter - graphic indicator of the effect of exposure changes.
Unique features including Intelligent Auto, Subject Tracking and this - shutter speed effect simulation.
HDMI output and remote release port.
Quick Menu, Film modes, Color Modes, and extensive photographic controls
Push and turn rear control dial.
The same fast contrast-detect autofocus system as the G1/GH1, offering 1-area, 23-area, face detection and AF tracking modes.