As I recall the powers combined with shooting was really new to the genre, along with the ways you combine them. Lighting enemies on fire who would run to water to put themselves out, then hitting water with electricity to zap a group was creative stuff. The way big daddies acted like a boss fight you could tackle in a bunch of different ways was significant too. The options there and with many other obstacles gave player agency for how to navigate most non-linear levels that was a real rarity. For instance, those turrets - have you shcoked them and hacked them? What about freezing them and hacking them? Or using hypnosis on enemies to make them fight the turret? But hacking all those turrets makes for a great distraction in a big daddy fight. And breaking the turrets gives you more ammo.

At the time most shooter were “go here shoot this, go there shoot that” and hell, thats still really common. This game really shook it up, even if it drew inspiration from thief and system shock, it did a lot to improve and advance them. Combined with the unique environment, smart story line, and interesting characters there’s plenty of reason it sticks in people’s memories as an all time classic.