The floor looks likes it was installed incorrectly. The image is scrambled. Look for a loose tile and pull it out. Then slide the other tiles into place as this is a giant slide puzzle. Once you fit the last one in, the double doors to the room will close and lock.
Look at the ceiling to see the angel. You should see it pointing in a direction as well as something the looks like a hidden flap. Be careful, should you step on one of the tiles you slid into place, that flap will open and a set of bladed wings will swing down to strike the person who set off the trap. Should you step off the trigger, the blades retract back into the hidden nook.
Look for something heavy to place on the trapped tile to cause the blades to activate and remain in their open position. Careful not to get hit. Look on the blades to find the next clue:
"Where is the fallen angel pointing?"
Look at the floor tiles and see that the angel is pointing to a book stand. Open the book to the bookmarked page. There is the next clue.
"If a red door is made of red wood and a blue wall is made of blue bricks, what is a green window made of?"
Look at the shelf next to the book and there are two green glass vases. One is actually made of crystal. If you reach into it to search you will find a note that says:
"This one is made of crystal, not glass. Try again."
Go to the other one and reach into it to find the next note:
Try to remove the vase to find it acts like a lever. Pull it all of the way to open the next room behind the bookcase behind you.
There is a painting in the room that if you try to move it, it opens. There is a safe behind it. Look for the combination hidden in the painting and use it to open the safe to get the next clue and the key for the next locked door or container.
The door to the next room has no key. But there is a hole in the wall next to it that looks like it could fit something. Look in the room for that thing and place it in the hole to open the door.
The gate has no apparent method of opening it. There are mirrors all over the room. A beam of light is pointing to one of them. Manipulate the mirrors to guide the beam to the large crystal above the gate. This is a light sensor which will open the gate when a concentrated beam of light hits it. Careful not to touch the beam as it is as hot as a high powered laser.
There is a set of swords placed on plaques on the wall. Each one has a jewel in the pummel and the guard. They are of different designs and construction. Somewhere there is a clue that indicates that swords are in the wrong places. Place them on the correct plaques to proceed. (Make sure they are completely worthless outside of the Escape Room.)
One or more of your items might be stolen from you and placed in the room as a clue to something. (this is the thieves guild after all. What did you expect?)
There is a clue in the suit of armor. But in order to view it someone in your group must equip it and wait for a few seconds. After that, unequip it and look on your body. The clue is there.
Try to open the door and the knob comes off revealing a combination lock. The combination should be somewhere nearby. Program it into the lock and place the knob back into position. Turn it to open the door.