Map 1[edit]
You've hatched! Walk around the room. You need to find a ladder. Use the wallwalk (see alien controls) to climb it up. You will arrive in a vent. There is only one way ahead, just watch out for steam, it can hurt you.
In a tall room with a fan use wallwalk again. Eventually you will come to another vent but soon you will appear above a corridor. There in only one way, so follow it. Finally you will come to a space above the corridor with a broken grille. Drop down.
You've in a warehouse. Go into the vent again. Drop down. Careful, watch out for steam and electricity. There will be a lot of vents and wallwalking until you arrive above a lab.
The only way here is down. Drop on the table and scare scientists. Facehugging one of them is a certain death since you will be killed by guards. You need a solitaire target, so after dropping down run into the corridor and past the guards. You can use your facehug attack to cover big distances. It's safe as long as you don't hug someone's face.
In the corridor run ahead and go up to a vent in the ceiling. You will drop in another corridor. Go to the vent and to another corridor from it. There are two humans. Approach them carefully and they will leave the corridor. Go through the broken door and to a private room. That's the target you need. Facehug the poor guy.
Map 2[edit]
You start in a human chest. Press "attack" a few times to get out through internal organs. Now you need something to eat to grow. Dead human body won't do for some reason, so go out the window.
Note: You don't have a wallwalk ability now but you have an attack. You can't kill anyone with it except for harmless bugs, so there is no point in using it. More to be told, it will compromise you, so refrain from using it.
Go ahead trying to stay out of humans' line of sight. From the words you hear it's most likely that the guy you killed was named Cisco. Not that it gives you anything. Despite this level is long, it's not much that can be said about it. Hide behind covers, watch for humans, avoid them at all costs and save often.
Your destination is a warehouse guarded by a few humans. As you enter it, you will hear meowing. Look for a hole in a fence behind crates and get in. Now you can finally have a snack to grow into a drone.