So, a review of the entire riddle:
Accurate advice. Also quite easy, but only as long as the players receive the description of the painting with the tormentor creature while searching area 3.
Area 5 is the first arch they'll come across, and fits the bill.
and the second great hall you’ll discover.
The arch at area 5 teleports to three locations, only one of which is the hall in question. It's not enough to just 'go through the arch'.
Shun green. Gotcha. Green things in the Tomb:
- The green face in area 6. Lethal.
- Green sphere held high in area 10. Irrelevant.
- Pale Green sphere at the feet of a figure in area 10. Irrevelant.
- The tapestries in area 21. Highly dangerous. The description is easy to miss though when actually in that area. DM dependant in my opinion.
- The other green face in area 25. Not particularly dangerous on its own, but it does steal your equipment and teleport you.
- The other face in area 25 is 'tinged with bluish over the green'. Teleports party.
- When opening the door from area 25 to area 27 there is a sickly green shine. It's the sword room.
So it is good to avoid green.
but night’s good color
is for those of great valor.
This is highly problematic. Different people will interpret this differently and I don't think there is a universal good colour of night. Black, grey, blue, orange, purple, what? Useless tip. Might even be lethal if they think it's black and decide to use the green devil since "We'll be fine if we don't touch the green parts when we jump into its black mouth".
If shades of red stand for blood the wise
will not need sacrifice aught but a loop of
magical metal - you’re well along your march.
Red things in the Tomb:
- Red tiles in the entry hall. Snakes so that they avoid two pits, and lead over four.
- Red sphere in area 10. Leads to area 13 and the three dangerous chests. And remember, the first person entering the room gets automatic damage.
- If the altar in area 14 gains a red color, it is explosive.
- When the gem in area 25 begins to explode it turns red.
- In area 29 the door turns red when attacked and bleeds blood when cut. leviation magic used against the blood turns it into a red ochre jelly.
So which of those is it referring to? Why of course
none of them. It is referring to passage to area 15 which requires a magic ring, and which is associated with nothing red. Not unless they mess with the altar. Are they really supposed to fail here to succeed according to the riddle? And even then the colour isn't red, it's blue-red.
Two pits along the way will be found to lead
to a fortuitous fall, so check the wall.
There are two passages inside pits. Pretty straightforward advice.
These keys and those are most important of all,
There are keys. Remember to look for keys.
and beware of trembling hands and what will maul.
Completely useless advice. There is no way to avoid either the agitated room or the juggernaut based on this line, because you won't know that it refers to them until after you've gone through. Maybe not even then. There are no trembling hands in the Tomb, unless it just means for the characters to be generally careful and not go touching what they don't need to. Which should already be obvious to everyone involved.
If you find the false you find the true
and into the columned hall you’ll come,
As I already noted earlier, if you follow strictly what is said here, regardless of which order you take the 12/22/23 crossroads, regardless of which one you go into first, it
doesn't lead you to the columned hall. Most likely it leads you into the sleep passage.
and there the throne that’s key and keyed.
Investigate throne. Check.
The iron men of visage grim do more than
meets the viewer’s eye.
Ooh. Look at the statues.
You’ve left and left and found my Tomb
and now your soul will die.
This just says that there's something here, look closer. As Bullgrit said, just backtrack if you missed it. Keep looking.
So what is my final verdict? It's decent. There are a couple of points which might mislead to something bad ('night's good colour', 'shades of red', and the 'find false you find true'). But mostly following it might help you. 'Avoid the green' helps surprisingly much. But it is really vague, and a lot of this conjecture is from already knowing what the passages are referring to.
Meh.