You need to keep vigilant because the entrance to the buildings is guarded by a group of corrupt policemen, who are quite well-trained. Attack them by surprise, e.g. using the grapple or the concussion detonator. Right after the fights start, focus in the first place on eliminating the enemy armed with a knife. Furthermore, you should watch out for the SWAT team member wearing a heavy armor, as well as for the enemy with a shield (stun this one with your cape and stomp on him). Continue fighting until you have eliminated all of the enemies.
After the fight, enter the building and reach the door to the Hotel Parking. Also here, follow the linear path, while listening along your way, to the conversation with Alfred. Sneak up to the two bandits that you bump into here and take them both down with a single attack.
Below, there is a group of ten enemies and I recommend that you glide towards the martial artist shown in the screenshot to eliminate him in the first place. As a result, you will not have to worry anymore about dodging the faster and more demanding attacks. Further throughout the fight, you should pay a lot of attention to the enemies who will be trying to collect a gun from the crates on the sides and try to prevent them from doing that, to the extent possible.
Try to clear the entire area of the enemies and locate the control panel on the Southern wall. Select the Cryptographic Sequencer from the inventory and start the well-known hacking mini-game in order to determine the correct password (the screenshot). Remain where you have just used the sequencer and turn to the red button with the discharges guarding the access. The solution to this problem is simple, because it is enough to use the Remote Controlled batarang and hit the button with it.
Look up now and select the grapple from the inventory, and use it on one of the interactive points to extend the rope. Make it over onto the rope, using the hook, and jump to reach the control panel, which will unlock access to the parking lot. Return down and use the new passage., Locate the generator which you need to restart. You can now enter the Parking Elevator and wait until it takes you to the Royal Hotel Main Entrance.