Out of Space: Couch Edition

You must play on either Medium or Large difficulty. And you cannot play with Zen Mode enabled - this will prevent most achievements, particularly all of the "Unusual Way" series, from being awarded. Play on Medium to make this task just a little easier.

For this specific achievement, you cannot use any of the three furniture type that allow you to rest/sleep to restore your fatigue (ZZZ) meter. This means the chair, the sofa, and the bed are unusable. If you get a box with one of those in it, go and recycle it if you are working on this challenge. You're only allowed to collapse and fall asleep on the floor when you run out of fatigue/ZZZ.

To this end, you'll want to plan when you collapse, ensuring that chaos like air vents or gooey doorways are taken care of before you become unresponsive on the floor for many seconds. Once there, force yourself to run out of energy with actions that use up energy quickly: using the mop, or using the exercise bike. Latter nets you a little bit of $$$, while the former can be done anywhere if you have the mop on hand. After time passes and you wake back up from the floor, take quick action against dangers (vents, doors), then work on tackling the next room for cleanup.

There is also a "potted plant" furniture that restores a tiny bit of fatigue if you are in the same room. This hasn't been tested, but you can probably use this to help with resting. Unfortunately, the store only stocks it once you complete this challenge, so this only works if it is found in a random box. If you are lucky, put it in a room you intend to use up all your fatigue in, to sleep just a little faster on the floor.

The above management of when you fall asleep is important. As you open doors to goo-infested rooms, you'll end up with 4 aliens bum-rushing you, requiring you to use the mop and water buckets to stun them, then other devices to dispose of the aliens (recyclers, mixers, macrowaves, etc.). This will wear you out, so you will want to have an empty fatigue meter before tackling them.

Worse, there's a "fungal" alien upgrade whose spores will wear you out. If you are going for No Resting, these enemies are your bane. Once they're turned over, there may still be a sleep cloud around them which can still affect you, so getting rid of these enemies when they appear is job #1. Job #0 is to stun and take out the "Boost" aliens if they appear as well, since they'll only make thing worse in combination with "fungal" aliens.

Other tips:
Since mopping is a tiring activity, see about getting a Cleaner Bot early on. You'll need to unlock the recycle 250 item achievement (Think about the environment!) for it to appear in the store for $40. You can have more than one.
Get more dogs to help zap aliens, particularly if "fungal" aliens appear. Less mop usage means less chance of falling asleep and getting slimed by nearby aliens.
If you are getting close to max fatigue when trying to clear out a dirty, slimy, alien-infested room, close it up and wear yourself out in a safer room. You can try again after rested, and it takes a little bit of time for a regular alien to upgrade, giving you a chance to try again with hopefully less problems.
Lastly, don't forget to keep yourself fed, as well. Starving after fainting, especially close to the end of a round, is painful.