Yeah, you can play almost every Steam VR game on an Oculus Rift. There were a few early games that weren’t compatible (Bethesda, due to the lawsuit, for instance), but there are utilities that will let you play Rift games on Steam VR and vice-versa. Oculus has lots of exclusives, on the other hand, but those can be hacked onto other headsets too.
At any rate, Half-Life:Alyx is amazing on the Rift S.
At any rate, much of the design is around being fully immersed in the environment. Certainly the controls can be reworked so it’ll be playable in 2D, but without the gesture motions, the physics of using the controllers, and feeling like you’re in the environment, it’ll just be another FPS.
It’s how well the controls work and the environment feels in the headset that makes this different.