What this movie did wrong...
Opposed to many reviewers and commenters I actually enjoyed this up to the third act (or rather half way through the second act) however there was really a missed opportunity here. This had evil dead written all over it, and it really could have been a throw back to it. As such these are the things (and reasons why I'd have changed them).
First the girl should have died. I'm sorry but in my opinion she was way too uptight etc in the first half to warrant her becoming the heroine in the second: she should have been impregnated by the queen bee.
Which leads to our second point, the main guy should have had more heroic/comedic rescuing moments. They kind of hint at it but after the main massacre they seemed to have lost the budget to keep the pace going and it came to a standstill. With these they could have clarified and developed the character rather than switch it halfway through to a girl who is fairly unlikable.
Instead of hammering a reason for why all this is happening, have the half man half bee be torn between the two worlds and explain a bit but not the entire story. His explanation of chemicals etc kinda cheapened it to return of the living dead 3 territory where it just felt forced to explain it as opposed to central to the plot. Have him inner monologue between his two sides about how they're far more sinister than appearances have shown and that they have big plans, but leave it a bit vague. This really could have led to some really comedic moments/arguments between the two especially considering it being played by quite the decent actor.
How do you cast lance hendriksen and make him seem bored. He was one of the most interesting characters in the film yet he was under utilized. He's always wanted to be in a comedy, so give him some proper material and I'm sure he'd go out of his way to perform in a more lively role. That and give him some balls out killing scenes (maybe a scene where he helps wasp boy tear out part of the wasp in his hump or something) then if you're going to kill him, give him an awesome death. Maybe after the impregnated heroine comes back for one last scare have him drop kick her into a fire from the roof screaming bombs away b($(;h!
These are just a few ideas but in my mind Galway through this film I thought it was going to turn into a balls out return the the horror comedies of old but then turned into a mediocre sought of cost saving scenes and bad dialogue that just bogged the movie down.
It's totally worth a watch, especially up to the first big massacre (even if some of the cgi is janky). But it's sad imagining what this could have truly been and what it truly was :(