Level by Robert LaChapelle
Walkthrough by Phil Lambeth, with reference to information contained in the previously posted walkthrough. There are only limited references here to the astronomical significance of the symbols you encounter as you play. Only the actual solution is recorded, which makes for a "level" consisting of a single puzzle that takes only a few minutes to complete.
Be sure, after you convert coastal.tom, to rename coastal.tr4 to planets.tr4. Otherwise, you won't be able to play the level.
Lara begins in a stark white setting, facing a black rectangle oddly reminiscent of the monolith from 2001. If you run forward toward the blackness, the camera remains fixed until you emerge in a planetarium with all planets being depicted on the far wall except Earth. On the floor ahead of you you'll see a series of circles and dots, representing those eight planets and the number of known moons each had at the time the level was released. On the near left corner is the sun, and to round out our solar system the Earth and its crescent moon are located at the near right corner.
The procedure here is deceptively simple. When you begin, the floor (or more accurately the game board) is inert except for the sun tile, which would kill you if you were to step on it now. You need to activate the game board and turn off the blazing sun in order to start. To do so, go to the right side and walk over the Earth tile (whereupon you get a fixed camera angle) and the crescent moon tile (which triggers the game board "on"). Back flip to your starting point in the black area in front of the game board. Without stepping on any other tiles, go to the other side and step on the sun tile which is now safe.
Hop back to the black area and side step to your right. Step on the first light red circle, which represents Mercury. Someone speaking in a guttural voice says something that doesn't sound very polite. Mercury is moonless, so the square ahead is empty. When you step forward, the camera angle changes, which is your clue not to move forward any further. That's the pattern you'll encounter as you navigate each of the next seven rows, working your way to your right one row at a time. When you get a remote camera shot as you step forward, that means you've reached the tile representing the number of the corresponding planet's moons (whether they be major, represented by the dark red circles, or minor, represented by the dotted tiles). At that point you need to hop straight back or back flip, being careful not to touch any of the tiles on either side, until you reach the black area in front of the game board. Then side step to the right and repeat. Each time you start a new row, you'll get a different sound effect. When you reach the next to last row, representing Pluto (which has one known moon, Charon), step forward to the first dark red circle tile, then turn right and walk across the crescent moon tile to end the level.
That's all there is to it.