Thank you very much for playing the game! We weren't expecting a feedback so soon.
You can attack the tank enemy (shield guy) after he is tired. To quickly wear him out, you can dash around him to dodge his attacks and he will become tired and open to attacks.
Initially, the player didn't need to interact with the doors to open them, but the player near a closed door could unintentionally walk into it when it opens, so we decided to make the doors interactable.
Thank you very much for the feedback!