"Blockers" have funny scenes; characters are well-fleshed and there are interesting (an quite new for mainstream comedies) themes about sexuality of youngsters. But it lacks the heart of Rogen/Goldberg scripts for "Bad Neighbours" and "Bad Neighbours 2" because of an apparent separation of two plotlines (parents vs kids) that rarely intertwines.
As with the original, the best parts are: grounded story (not saving the world — saving Mom); Michael Peña (esp. EdgarWright-esque montage) and action scenes that make fun of features that are unique for these characters (seagull bit, kitchen scene, kid Ant-Man, truckboard, etc.). With the addition of Randall Park.
The worst parts are: the rest of the generic action scenes; weak structure (the ghost plot was particularly lousy); and the lack of chemistry between the three leads. Supporting cast delivers more laughs and excitement.