In my humble opinion, Control was a great game. The play was a little repetitive in terms of fighting battles and bosses, but I never grew tired of pitching furniture and chunks of concrete at red-glowing baddies.
With that said, there was a small issue with the original game in that the final boss wasn't really a boss. Enter - The Foundation.

While the overall level design and mechanics of TF didn't change from the main game, the platforming portion increased in intensity and they added a couple of powers to support the puzzles that you needed to traverse through the missions. Nothing too groundbreaking from the original title, but TF ramps up the difficulty of the platforming and the strength of the enemies you face. TF is also generous with ability points and allows you to unlock skills that may have not been completed through the original game.

More importantly, though, TF adds a proper boss battle that I found to be more challenging than any of the original content, so completing TF felt downright satisfying. The seamless way in which TF begins, it does not break immersion during the transition from the original game, so if you have not played Control, I would highly recommend adding the DLC and playing through the entire thing as a single experience.
