Congratulations on a smashing release! The mod is of downright stunning quality -- skins, textures, models, sounds, weapon balance, gameplay pacing -- "version 1.0.0" really doesn't do it justice.
However, I'm kind of curious about zap. Although it rounds out the marauder nicely, it seems unbalanced in practice.
I have two reasons. For one, zap imposes no restrictions of any kind on the user. It doesn't slow the user down, ask the user to aim it, or make the user worry about ammunition conservation (as do barbs).
My second reason is a bit more circuitous; please bear with me a little longer.
Human players arguably feel the effects of network latency more acutely than aliens, since their weapons are mostly hitscan and projectile. As they take aim, human players must not only predict the fast movement of their foes, but also compensate for lag. Aliens, on the other hand, use less precision and greater speed to joust at slow-moving targets.
So, with this in mind, zap starts to look pretty strange. Zap allows aliens to miss a target all together -- fly overhead, to the left, who knows -- and still score damage. Meanwhile, human players are struggling with fast moving targets and varying degrees of lag.
As I see it, there are a host of ways to modify zap. It could impose some "ground time" on the player, which temporarily takes away the marauder's best evasive trait -- bouncy, unpredictable speed. Alternatively, the damage could be toned down, or the reload time inched up. Coolest of all would be an implementation of unlagged2 or something like it, so that latency would no longer be an issue.
Anyway, congratulations again and kudos. Tremulous is incredible.