If you build your elevators in a certain way you need a ton but you just need two on each floor. As if you stagger them with the top of two and bottom of another two overlapping on a floor it stops the elevator having to travel miles for passengers and therefore not getting other passengers for ages. Perhaps 3 per floor for the biggest hotels. Worked for me, I thought it might and did major remodelling!
To dev; You may or you may not read this. Only one annoying thing that I found when playing which was when I went through a door, just before I heard the ceiling giving way, so a horde coming through. they were then spazzing out on the door and killed my companion. At which I was trying to fight off another load coming from a different hole, pressed g to revive, must have pressed it again and lost my best gun to the companion and then died so I couldn't get it back.
Apart from that I say its a 5/5 game, I have always loved your last stand games!
Well done it could use some things like Music, and maybe some different balloons and achievements but if this is a first try using tutorials I would say very very good. 3/5 for the effort and the mad vampire thing!
Play again from a level that you lose from would be good as you then wouldn't have to restart every time you clicked or pressed space at the wrong time.