I have not found what it do exactly. I seem to do little dammage but I think I heard (so it's not a tangible information) that is slow Ennemy too...
If it's the case, will is slow the human when it wall on the splach on the ground (that create big creep like splatch) or is it needed to hit the personne ? As Adv. Granger is not (realy ?) build to fight, It can be a good tactic to spay if it has a real effect (My test are not... result full.). I'm just using it in order to place false defenses places (as the splach is like creep...).
Is it possible to have a cross to be able to aim with the Adv. Granger ? It has a balastic beaviour so it is very hard to use... (May be this can help to hit down jetpacks...) For the splatch glue, if it not the case, may be a 3 stage builder upgrade can be implemented (but not free of course) ?