Constant altitude descent
A landing maneuver performed at low altitude (~5km) above the target body. The spacecraft burns slightly anti-radial (towards the ground) of retrograde, keeping its altitude constant. This trajectory can be more efficient than a gravity turn or direct descent because the entire burn is done as close to the surface as possible, taking full advantage of the Oberth effect. If done right, this gain outweighs the gravity drag of maintaining altitude.
Constant altitude descents can only be performed on airless bodies. It works well with low-thrust landers. Not recommended for pilots prone to motion sickness. Look out for mountains!