Despite the open world, a traditional LEGO experience can still be found in LEGO City.
The LEGO City: Undercover trailer impressed at E3 with its clean graphics, its humor, its open world and the general feeling that it was trying something never done before in the dozen-or-so LEGO games that have preceded it, but Jonathan Metts having played the open world demo right before me, I found myself choosing the "Mine" demo which delivered exactly what you expect from a LEGO game.

As Chase McCain enters a mine in pursuit of some manly, hairy criminals, he soon finds out that to get anywhere, he will need to get some dynamite from the dynamite dispensing machine (!). But before you can help him do that, you will need to find a miner costume. Running around the area on ground level, I came across a locked door. I switched to McCain's second costume, a criminal's outfit complete with a crowbar, to force the door (mashing the A button) and get some studs inside.
I was on the wrong track. I got out of that room, looked around, and generally looked for stuff to bash into pieces, which could be used to build something new by holding down the A button. Sure enough, that turned out to be the answer, and Chase built himself a little ledge to access a higher floor in the mine, where I would have to do a bit of traditional platforming. I was disappointed to see that I wasn't given any opportunity to do any of the acrobatic moves shown in the trailer. Swinging on a rope was basically the most advanced move that would be asked of me.
I got to the miners' locker room and found my costume, gaining the ability to break rocks and, more importantly, acquire dynamite. The dynamite worked perhaps a little too well for Chase, as the floor gave out and he found himself free-falling through a vertical shaft. I initially tried to steer him by tilting the GamePad, so used I am to the Skydiving game in Wii Sports Resort, but as it turned out you simply used the stick to move and the B button to accelerate. In fact, the GamePad's capabilities didn't seem to be put to much use in this demo, as I don't recall having to look at it at any point in the demo.

Having reached the end of the shaft, Chase releases his parachute while making a comment about how happy he is to have packed it that morning, and after bashing a few more rocks, gets to the green LEGO blocks out of which he will build a Super Mario pipe and enter it, with the appropriate sound effects. The demo ends on this.
The classic LEGO formula remains fun for those like me who have barely played the previous games, but it is to be hoped that these more traditional missions don't make up too much of LEGO City: Undercover. Travellers Tale does what it does extremely well, and the platforming or the humor certainly weren't below the level of quality that we've come to expect from the developer, but with the tablet features being mostly used in the open world part of the demo, clearly that is the part of the game that those looking for something new should look forward to.