Escaping Area 51

You tried to break into Area 51 and got caught. While locked up deep underground, Scientists working on portals to other dimensions, unleashed creatures into our world. They have wiped out most of the staff and guards. Now, you have to escape from your cell, eliminating the creatures and remaining guards as you go from floor to floor trying to make it to ground level. You'll find Chest along the way as well as getting Gold and a Keycard for eliminating Megabrute creatures.