Nice work 

 but 

Isnt map too bright? 
Maybe the middle is a bit too bright but the rest is good.
 What do you think about a default bases?
The default base are too weak but its goodbecause it force team to move.
 Is game balanced? 
Absolutly not, human get advantage because of
 - their anti-tyrant spot
 - there is no aviable spot for alien
I can't explain why alien win 2 time this morning but the map isn't balanced. What would you change in next version? 
More spot is key for a better map.
Actually you should improve theses spots (enlarge them): 


PS : Did you correct the tyrant bug?
PPS : You should remove this map leak : 
