There are two walkways extending out into the water - take them out, then zip round the back to collect the special weapon crate!
These tunnels transport you to the top of the level, ejecting you from the museum entrance and vice versa. Use them to get to and fro the upper and lower levels in order to collect powerups or escape attackers.
These huge generators are recognisable by the purple electricity they produce. When you hot them enough times, the explode sending huge chunks metal in all directions. The blast radius is pretty huge, resulting in high damage for anyone caught nearby. Use this to your advantage and wait until there are several vehicles nearby before targeting them.
Not so much a feature, so much as a secret area, if you come off the road at either side you should be able to take up position on the roof above the tunnels. This is a good vantage point and is relatively safe from enemies above, though you should destroy the pylons here if you're planning on hanging around for any period of time.
Much like the original, just drive between the buildings until you come level with a large handle. This fires an electricity bolt along the channel, inflicting damage on anyone foolish enough to be caught there. You can even use it when both buildings have been totalled!
These can be activated either by clipping them on the way past, or hitting them with a weapon (including the machine gun). They only fire in one direction (i.e. out of the tunnel that isn't pointing towards the water channel). The best use of this is to trigger them when the tunnel is full of enemies, though if you're quick enough, you can tag them on the way past an esapce before the water hits you, useful for losing a tail.
There are about half a dozen of these types of jet, you can activate them simply by passig over them. Slower vehicles may struggle to escape the resulting blast, but they don't seem to do any harm either way. A far better use (especially for light cars) is to set them off, then afterburn into them. Timed correctly, you can often launch into the air and land on the road that winds round the level!
If you look at the sides of the main road, you should notice that many rock formations stick onto the tarmac. In fact, you can shoot most of the rockface at the edges of the road and it will create a mini rockfall. If you're being chased, firs a few rounds into these areas and the resulting debris scattered across the road may be enougn to lose your assailant...