I didn't watch it for the cast, I wanted a 90min movie to fill some free time. I've now watched it three times and would do so again.
I realise my sense of humour is 'off' but this genuinely tickled me, it's up there with Cockneys vs Zombies, or the original Police Squad! TV series. A knowing parody with a decent sfx budget.
I suspect some studio exec demanded that Arnie featured heavily in the publicity which was a floored decision and has only delivered criticism from the 'wrong' audience. Movie going is about being entertained, a suspension of disbelief, not slavishly watching a beloved face from other films... and then the poor reviews flood in.
I dropped it from 4to3 stars on my third watch because it doesn't hold up as well to my standards. 3 stars is still ahead of the peak and to my mind reflects a well crafted film with no obvious faults... I only rate Star Wars (ep IV), and Chocolat as 4-star movies, and all the Matrix sequels as 3-star.
Anyway, if you enjoyed The Office, laugh at OTT kills (think Scream & Final Destination), and enjoy Rick & Morty, and aren't 'precious' about your actors ...
Watch this film, all of it, right to the close of the credits.