Alright, I took PN for a test drive late last night.
Construction:
It's a bit tedious - takes a LOT of keyboard inputs to place a few blocks. I don't like that the block changes it's axis depending on which surface of another block you're pointing at. Blocks also don't remember the position/angle of previously-placed blocks. So as you change from block to block, you have to keep readjusting axis's even when making a single row of blocks (say, transitioning from a square block to a point.) Generator block: PLEASE give this block more mounting positions. The fact that it can only mount to a block on the bottom is NO GOOD for such a critical and LARGE block. Also, I placed two cubes along the bottom, rear edge of the cockpit. I then selected the generator, and pointed at the back of the cockpit, and rotated the block until the bottom of it was facing downwards, against the two cubes. The block highlight was RED and it wouldn't let me place it. When I then pointed at the TOP of the cube blocks and re-rotated the block to the exact same position, it then highlighted green. I'd consider this a bug and will report accordingly. Just thought I'd mention it here as well.
Another problem I encountered was while building my first car. I gave it a pointy nose (because I could,) but apparently the blocks were so heavy that when I place the wheels and removed the jack, the front of the car collapsed to the ground, and no adjustment of the shocks could lift it back up. I had to delete the blocks completely, and in the process the suspension fell off and I couldn't lift the vehicle back up to fix it. I had to simply start over.
Suggestions:
1. It was posted here elsewhere the suggestion that control, shift & alt buttons be used as modifiers while constructing. For example, control+mousewheel could change which axis (blue/red/green,) while mousewheel alone can rotate along that axis. Shift+mousewheel could scroll between block selections (1 through 0) and perhaps alt+mousewheel could scroll between block "families" (ie from a cube block to a slope block to a corner block, etc.)
2. Make block orientation relative to grid, not to surface of block pointing at. This will make large construction projects much less frustrating.
3. Give generators mounting points on each surface "area". A critical block with 16 surface areas cannot only be mountable on 2 of them - it makes "small builds" very, very difficult.
Settings:
I LIKE the tab screen - I like being able to configure the various wheels, pistons, lights, etc, independently. I truly hope to see these options continue to expand and offer more customization. I'd also love to be able to assign hot keys to, say, stiffen the suspension while driving, or swap from a single-axis steering to dual-axis steering on demand. My only suggestion here is to make sure it's clear what the CURRENT setting is. I couldn't tell if I had to click to turn power off, or if power was already off.
Driving:
Needs a LOT of work on the physics. Several others have already mentioned the poor traction of those huge tires. Also, the vehicle slides on the smallest of slopes - you need an e-brake for sure. Also, I put spotlights on the front "bumper" of my car (since it became night almost immediately after starting the map) and they would light up when the car was sitting still. The moment I started driving in any direction, the lights would turn off. This was on both manual and automatic settings for the lights. Also, I couldn't personally tell any difference between the speed settings on the wheels, but perhaps the suggestion I saw elsewhere to add more generators would help.
I also had some flickering on the screen as I was moving in the car - I have yet to test whether it was my graphics settings or not, so I won't report further until I can do more testing. The environment though was pretty nice, for what little bit I got to see in the daylight.