AREA 51, Down
The few bugs in the five classics that help you descend.
This works in all games through TR5. Dive to the base of a vertical wall and Lara lands with no damage! But the takeoff position and angle usually must be precise.
Here's an example from TR4's Catacombs, at the platform on a high column. Go to the southeast corner of the platform. Face the south wall and turn Lara to between these two angles:
However, this angle doesn't work!
So I suggest aiming at the middle or left side of the range. Then hop back, step back, let Lara come to a complete stop, and step back again. Now take a running dive.
The stop is necessary because two continuous steps back are slightly longer than two separate steps.
Here's a video that shows an earlier trigger bug at the opposite corner of the platform. The first angle (at the corner) must be precise
Sidestep Descending Bug
This works only in TR1. The easier method works on collapsible tiles; you can even land in spikes without damage.
This video shows Lara sidestepping into the bug. The earliest reference to this bug that I know was on Jan. 25, 1999 at Theresa's site (tombraider.com) by Jose Ribeiro, but he reported it works by walking back a step, which is also true.
The more difficult version, reported by TombRaiderSpeedrun in 2011, works by moving forward or back to be partly off the edge, then sidestepping toward or away from the platform. The first video has a clip for running forward, and the second shows hopping back.
Crawl Drop Bug
This bug is infrequent in TR4 & TR5, but shows up often in custom levels. It allows you to drop from a great height without damage. Discovered by xXApelaumXx.
Walk up to a diagonal edge until Lara turns off course. Face approximately at the diagonal and jump vertically once. This angle is fine.
Now rotate Lara so her back is to the edge; the angle shouldn't be too parallel to the diagonal ledge, but it hardly matters. Hold Action, crouch and back up; she will turn toward the invisible edge which she's nearest to pointing her feet at, instantly translate to that edge, and perform the bug.
If you keep holding Action, she stays underground.
When you release it, she pops out, as if propelled by a spring.
Here's a video of the bug in action.
Here's a variation in TR5 with an irregular edge.
And an example from a custom level which works at a lowering ledge.
In TR3, it starts to work at a diagonal edge, but Lara becomes frozen hanging from the invisible edge.
The main entry for this bug is on the "Other Bugs" page, but here's a case found by xXApelaumXx, which features a long fall to count a secret.