[ANALYSIS] Planet X and Doors

Planet X is Taz: Wanted's way of allowing you to go back to previous hubs: you enter a door located in any of the game's hubs, taking you to Planet X, then you enter another door, taking you to that hub.

You may at first think that Planet X is a separate map, apart from every other hub, but that is incorrect: if you notice, there is no loading screen when you go to Planet X. Not only that, but the hub's music continues to play when in Planet X. The truth is that there are four Planet Xs, one in each hub. They are located under each hub, far below the death plane (going to Planet X disables the death plane, though it is reenabled once you return to a hub. If you go out-of-bounds in Planet X (which is possible) and fall, you'll fall forever (there may be a limit, but I've fallen for over twenty-four hours once and hadn't reached it) and if you were to go back to the main hub area by any means excluding the door, the camera would be stuck in the Planet X section).

As such, there are actually 20 doors (22 if you count the Disco Volcano and Hindenbird doors) in total. Here is how to unlock them:


YZ Door			- Complete ZT, IB, LL and EP
YZ -> YZ Door		- Complete ZT, IB, LL and EP
YZ -> SF Door		- Complete ZT, IB, LL and EP
YZ -> WEW Door		- Complete ZT, IB, LL, EP, SM, Ld, BoS and GT
YZ -> TL Door		- Complete ZT, IB, LL, EP, GC, TH, CSM and DC

SF Door			- Always Open
SF -> YZ Door		- Always Open
SF -> SF Door		- Always Open
SF -> WEW Door		- Complete SM, Ld, BoS and GT
SF -> TL Door		- Complete GC, TH, CSM and DC

WEW Door		- Always Open
WEW -> YZ Door		- Always Open
WEW -> SF Door		- Complete ZT, IB, LL and EP
WEW -> WEW Door		- Always Open
WEW -> TL Door		- Complete GC, TH, CSM and DC

TL Door			- Always Open
TL -> YZ Door		- Always Open
TL -> SF Door		- Complete ZT, IB, LL and EP
TL -> WEW Door		- Complete SM, Ld, BoS and GT
TL -> TL Door		- Always Open

DV Door			- Complete TL
HB Door			- Complete DV


As you can see, there is no way to sequence break into Tazland via Planet X. Even if you could wrong warp to levels from the earlier hubs, you'd just continue from that point forward instead of abusing Planet X doors.