Glitchy and exploitable how? And I’d say the boss fights fit perfectly in the regular game loop because every time you’d come to something like a boss fight it was really just introducing you to a new regular enemy type.
I remember the first time I fought the breaker, roid rage freak, and I burned through my entire stock of ammo and molotovs. And I never wanted to see one of those things again. But then they were added to the regular enemy spawns. Driving around at night, oh shit it’s a breaker. Cleaning out a nest, fuck it’s a breaker. The game kept the tension of exploring and fighting high by continually adding new challenges and as long as you kept going you’d get new ways to deal with those challenges.