Hamunaptra is a very open, Egyptian-themed map that was originally designed as a duelling map for Quake 2. It is not exceptionally large, and although it might seem easy to get lost, navigation around the map is a sinch once you've played it. Both teams are offered relatively good base locations right at the very beginning of the game, which is a great thing, due to both bases' terrible initial positions.
Since this map was intended to be a gunfighter's map, the Humans have a definite advantage over the Aliens in terms of map construction. Wide corridors allow plenty of room to dodge and strafe the big aliens, while long lines of sight open up a cornucopia of sniping opportunities. In addition, the Humans' ideal base location is but a climb away: the rope ladder at the back of the base, near the debris pile, leads directly to it. Come S2, the Humans can move the reactor and essential structures onto the balcony above the indoor area's entrance, making them all but invulnerable to any Alien offensive besides Dragoon sniping. Even then, Dragoons sniping from the initial base location have almost a blind shot up to the balcony, making any sort of targeted attack practically impossible.
It seems that the Humans have advantages in spades on this map. Offensively, a group of two or more fully-upgraded Humans can take on practically any threat posed by the Aliens; two experienced Chainsuits can easily push all of the way to the Alien base without much resistance. Chasing wounded aliens is almost required on Hamunaptra, since the long corridors make it almost insane not to. From a base-raid standpoint, the Alien starting base is a joke, and a lone rifleman can easily destroy it given time. If the Alien team does not move, the Humans will win, or at least tie. Provided the server has enough build points and the Human builders have used them well, Humans rarely lose extended games on this map.
While the Aliens are at a severe disadvantage on this map, they still have their usual tricks up their sleeves, and indeed, one or two of the things that help the Humans also aid the Aliens. The same long lines of sight used by Human snipers can be used just as effectively as long retreat paths; Tyrants, with a single charge, can be far enough away from a human attacker to render his attacks relatively useless, and Dragoons can pounce at the full extent of their range. Attacking in numbers is also easy, since the corridors are so wide. Alien ground mobility is essentially magnified twofold by this map.
However, the Aliens suffer from quite a few problems. Besides the numerous Human advantages, the inital Alien base, for starters, is virtually indefensible, and is quite vulnerable to even the smallest of Human incursions. Additionally, their best base location isn't terribly good, either, despite the fact that it has a single entrance. Furthermore, the Alien team can't effectively move their base until Stage 2. It is therefore required that the Alien team go on the offensive, in order to prevent any Humans from getting to their weak base. However, in order to succeed on the offensive, either the Alien team must be very good, or the Human team rather bad.
A skirmish room outside of the Alien team's best base location. The opening to the right leads to the potential base location, while the opening to the left leads to the Alien base. A corridor on the bottom left (not shown in picture) leads to a staircase, another skirmish room, and eventually to the Human base. Notice the openness of the room: it is huge by Tremulous standards.