Really nice layout and gameplay.
Alien base needs to be fixed, those gratings look ugly and the base itself could be even worse than Tremor's default. Needs more corners, boxes, ramps, etc.
I think the ladder on top of the human base is a brilliant idea. The human base itself seems to be a bit too powerful and jetcampable like karith default although one can't say for sure because of lack of playing.
Overall the map needs more interesting details like boxes, perhaps pipes in the ceiling and so on. The rooms could have some more variety like ramps touching walls (cf. human side entrance in Nexus6) and other things like high stack of boxes making each room have an advantage, small or big, for certain team or class.
Vents are cool (if done properly

) - a vent to alien base would be nice if it would be placed so you can't shoot anything from the vent, only if you exit it.
The hall next to the alien base with the pipes looks great, although it could have something else braking the basic straight corridor. More of that!
Very nice for a first map. Keep improving this map, it's bound to be awesome!