I can tell that a lot of work went into the level and it definitely adds to the atmosphere. Listing the objectives is also a big help.
If you continue this project you should definitely focus on damage feedback. It's difficult to tell when you've hit something and it's not obvious when you're taking damage.
Because I didn't see anyone else mention it, movement gets slower when you're looking up or down. I've had similar issues when I try to rotate the input vector by the control rotation. The key is to only use the yaw and ignore pitch and roll.
I can also see small jitters in the arms when rotating the camera. This is another issue I've had before. If it's the same issue then it's caused by setting "Use Controller Rotation" on the pawn and also having "Use Controller Desired Rotation" on the Character Movement component. They've both useful tools but you don't want to enable both at the same time or they will both try to update and cause that little jitter.
Lastly, the arms don't look up and down with the camera. My preferred way to do it is in the animation blueprint. But one simple way to do this is to add a spring arm with "Use Pawn Control Rotation" set to true. Set the Target Arm Length to zero and attach the character mesh to the spring arm. Be sure to disable "Do Collision Test" on the spring arm.