Dark Heart is the 9th mission of Crysis 2. For this walkthrough, players will infiltrate the alien "Hive" superstructure, in hopes of sabotaging it, and perhaps learning more information about the suit and the alien infestation. This level is significant for housing entirely alien enemies, and as such is quite tougher than previous missions.

1. Make your way straight down the tunnel. You will get a mission update pretty soon.
2. Head towards the objective.
3. Note: nanovision is quite useful here, as the area is quite dark.
4. You will face quite a lot of alien enemies here, so be ready.
5. Note: don't let the aliens get in melee range of you as they tend to hit very hard. If they DO get in, make sure to melee them if you run out of ammo. It is also a good idea to try and fight them 1 by 1 as they are a lot tougher than soldiers
6. The Rocket Launcher may also prove to be quite useful here, especially versus large groups of aliens.
7. Take the high route when you reach the metal steps, instead of continuing on the ground level. This will allow you to snipe the aliens down below from safe position.
8. Watch out for the melee alien running at you, across the pipes, and clear up the aliens down below
9. Continue on the ground level.
10. Go into the objective door.
11. Crouch under the ventilation to get through towards the new objective.
12. Pick up the new weapon. It is DEFINITELY worth picking up as it deals a huge amount of damage compared to normal weapons.
13. Light the fuse at the objective and step back.
14. Continue on into the heart of the hive.
15. When you get into the large open area, you will once again notice a large number of aliens, along with those large armoured ones you fought in the previous mission. Choose your approach (using tactical options if preferred) and head towards the objective.
16. Press F at the objective, and continue on to the other objective locations.
17. Pick up the sniper rifle on your way to the second objective. It is very powerful, and you can use it to snipe off aliens in the new open area ahead. It only takes about 3 shots per alien, and only 1 shot for the head.
18. When you break the second "spore" immediately jump up to the broken roadway above and continue on to the third and last spore.
19. You will see the roadway crash, so you'll have to go across the alien structure to get across.
20. Continue moving along the spiraling pathway up towards the last objective. If you do happen to run out of ammo, you can always made do with meleeing aliens in Armor mode. It's actually quite efficient. Just do try it on the big guys!
21. Clear out the aliens around the last spore. Using the rifle here is quite useful, to headshot all the weaker aliens and then take out the big guys 1 by 1.
22. Sabotage the last spore.
23. Enter the central alien structure by following the objective arrow.
24. Follow the on-screen instructions to climb up.
25. Go straight down the roadway behind you.
26. Run towards the new objective. No enemies here, just sprint!
    
27. Even if it seems like you won't make it, the mission will complete.