Just some feedback and suggestions.

It's a bit boring to be honest, the same grind up the floors with very similar npc modes like protecting the hostage that you see in the main game. You could possibly extend it to get him/her through the next couple of floors.

1. You could make this a little more strategic by restricting ammo crates to every nth floor only allowing pickup of dropped ammo and introduce some aoe damage like gas pipes to compensate for reduced ammo. I think that would make it a little more challenging. Possibly start on the 1st floor with only a pistol and gradually pickup weapons along the way?

2. I've not been all the way up yet so my next suggestion might be already in. You could make part of the structure on fire forcing the player to traverse the outside of the building, getting picked off along the way.

3. Possibly put some of the bosses in the lifts when they open.

4. Some of the rooms have balcony's but no stairs to get to them? Who makes a balcony that you can only access by climbing up a box?

5. We got access to the watch and if it had a new feature to allow hacking of bots that would make the game a little more dynamic. The hunters can do it!

6. Introduce wild animals that attack you and cause bleeding. Some of the bosses could use them, like hyenas.