|N version||1.2 and later|
Method 1 (Easy)
The name of the level refers to the four guided zap drones in the bottom left corner trapped by a door. It looks at first as if the door cannot be opened but it turns out after a bit of experimenting that the switch is actually behind the exit switch. However, there is a way to avoid that problem.
At the beginning, climb up to the top shaft. There are three ways to the top. The easiest way is to hit the launchpad and then to keep walljumping upwards. The fastest way is to land at the corner of the launchpad and the wall while simultaneously jumping off against the wall to create a "super jump" which will get you to the top in two jumps. This is somewhat difficult though since the wall is so short. The final alternative is to collect the gold by walljumping the left wall, though you have to dodge the gauss turret. It actually is quite simple if you move fast enough, though the last two pieces of gold are slightly tough to get without being picked off by the gauss.
Run through the shaft, hitting the door switch and the trapdoor, which will spring up behind you. Drop down and aim for the gold at the left side, over the homing turret. Hit the diagonal launchpad, and land on the ground. Here, try to tap the switch really lightly - due to the fact that the door switch is smaller than the exit switch, it is possible to activate the exit switch without even springing the door switch! If you do hit the door switch and you release the "hounds", it is probably best to restart, since getting through the tunnel system with the zap drones is difficult. It may help to kill off the rocket before attempting this trick.
If you do indeed release the drones, you can wait for the drones to exit into the large space of the rocket room and reach the passageway. Or jump over the drones while in the passageway (very tricky).
Hit the vertical launchpad, then climb in to the entrance of the tunnel system. Kill off the rocket if it followed you in, then get to the very bottom. The mines should not pose a problem. When you exit at the bottom, repeat what you did at the beginning (unless if you went for gold, then try to use the speed way instead).