|N version||1.2 and later|
Method 1 (NEHS)
This level can be tricky if you're first starting out. Start on the roof of the first building. To get past this floorchaser, you need to jump down from the platform, then, jump over the floor chaser and to the right. Jump again onto the right platform and then to the switch. Get out by jumping onto the platform, then onto the ground and quickly back onto the platform before the floorchaser zaps you. Get through the doors and into the 2D buildings, so you can get all the gold on the right. Get as much as you can, but if you don't get all of it, that's okay. If you miss a piece of gold, don't go back, because it will take you more than 2 seconds if you try to get it. Enter the side of the building, activate the terminal, then hop on the bounceblocks to get to the rooftops, where you can simply jump to the exit.
Method 2 (Youtube video)
Method 3 (Skips floorguard part)
You don't actually have to do the floorguard bit at all. Just jump up through the two doors, get the gold on the right and the switches in the middle, and go over to the part with the zap drone. The drone's path is very, very long, so the timing here is trivial. Get the exit switch, get out of the left part, and jump up the bounceblocks, through the open door, and to the exit.