In the 90s, Sinbad was doing pretty well for himself in the family comedy genre. First Kid falls into that genre. It's a safe harmless comedy for all ages. Though it has, unfortunately, aged like milk. Watching it in 2020 is a challenge. Although it still has it's funny moments, it's just can't compare to other films in the same genre that have come out since. Where as films like Home Alone, National Lampoon's Christmas Vacation, or The Sandlot are timeless classics, First Kid definitely had it's expiration date. Brock Pierce was an OK child actor but he definitely needed Sinbad to prop him up. He hasn't done any films since 1997, so perhaps Hollywood was well aware of his limited acting chops. It's OK, child actors in the 90s were a dime a dozen and most of them have since moved on in their lives, Pierce among them.
If you want a safe child-friendly family comedy to kill an hour and a half, there are much better films to choose from, but if you've seen them all, give this one a chance. It is indeed entertaining.