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I Hate Mountains is the best looking custom add-on campaign you will find for Left 4 Dead 1. —Glenn (

Balancing the difficulty

Posted by Geoffroy in Development, Media, Progress

Tags: , , ,

Two weeks ago, we talked about the manor level and why we decided to do things the way they are right now. This week, the focus continues on the third level, the underground and on the overall campaign difficulty.

When Nicolas wrote the game design document about the campaign, one of the key elements was to build a rather long campaign with changing environments and gameplay. The goal was to provide players with a non-monotonous campaign that would work perfectly well as a whole, but also when playing each level independently. The global path had to be logical, but the gameplay type (open space/close combat) and the environment (exterior/interior) had to change beetween each map, following this approximative pattern :

Gameplay and environment evolution

As you can see, when you combine the different elements that make a Left 4 Dead level more or less difficult, we get the overall difficulty of each level. In game, this is pretty much correct for the moment, when testing we feel that each map is as difficult as it should be, and the third map is really difficult. Much like every official campaigns, we tried to balance the difficulty around the third map. The campaign starts slowly, progressively reach a crescendo at the third map (No Mercy’s sewers, Death Toll’s church, Dead Air’s construction site, Blood Harvest’s bridge) and slows down until the final arrives. But our third map is really hard.

At start, the underground level was supposed to be a catacomb-ish level, with crypts, coffins and all the extra cliché things you can think about. But when the prototyping time came, it was clear that it would never work the intended way. No one would ever want to walk in an endless network of catacombs and crypts during half an hour, plus that didn’t seem very realistic from the start. That’s why we decided to mix several underground environments in the same level. This choice was not really popular among the team until we all actually saw the result when the level reached a decently polished state. The different environments blended together perfectly well and if you didn’t pay attention to it, you didn’t even notice the changes until the end. For the moment, the level is composed of four different underground environments and architectures.

Iterative screenshots of a part of the underground level

The underground level was entirely made in a really short time, I’d say three weeks. Prototyping, gameplay tests, architecture and prop flooding were all completed in a matter of weeks. The only problem with this level is its length. For the moment, this is the longest level I ever played on Left 4 Dead. Taking the shortest path, it takes 3 minutes to run from the beginning to the end, while it only takes 2:25 on the longest Left 4 Dead level (No Mercy’s sewers, which is already a quite difficult level). For the moment, we believe the map is good as it is, because we’re able to finish it using the expert difficulty, but we are not against the idea of cutting a whole part if it’s really too long and difficult.

One of the key elements of making a level more or less difficult without interfering too much on its length and geometry is to tweak the item/weapon spawning. Unlike Left 4 Dead official campaigns, we decided to give more than 4 first aid kits in this level. Because the crescendo event is located in the middle of the level, you often reach it in an already bad shape… thus, you leave it in a terrible shape (if not dead), and there’s a whole half of the level left to do. That’s why we decided to give more than 4 first aid kits, because we know every player isn’t the best player in the world. The trap here is that we’re not really giving 4 extra first aid kits just before the crescendo event, so there won’t be enough for everyone… We believe it will force players to play efficiently and work as a team (or they will just insult each others and keep their first aid kits for themselves).

That’s all for the underground level, we are against spoiling everything before the release, so you probably won’t get more details before the release. On a side note, a few people asked us if we could give an approximative completion percentage for each level, so here it is:

  • Forest: 90%
    What’s left: soundscapes, items/weapons tweaking, nav tweaking
  • Manor: 60%
    What’s left: exterior, sounds, event, items/weapons, nav
  • Underground: 95%
    What’s left: soundscapes
  • Lumberyard: 50%
    What’s left: detailling, event, sounds, items/weapons, nav
  • Lakeside: 15%
    What’s left: everything except prototyping and ambient

Stay tuned for more developer banter until the release.


17 Responses to “Balancing the difficulty”

  1. Soviet says:

    Great post, I never thought the team was that professional until now. It’s good to know you are working so hard to balance it all out.

  2. vince&emi says:

    Indeed that’s excellent work, all of us are looking forward to play this campaign !!
    One (or two) questions however, will it be possible to play versus and the new survival mode with your new maps ?
    Thanks a lot for providing us this.
    After Portal Prelude I am definitively your fan :)

  3. sterfield says:

    I can’t wait to play this campaign, this looks awesome.

    Thanks for bringing such good stuff for the community.

    On vous attends avec impatience :)

  4. Sl@yEr says:

    Your diagram is so Valve-ish :)
    I can’t wait to play this campain!

    Et en plus ya deux Français dans l’équipe! :D

    Bon courage les gars!

  5. Geoffroy says:

    Et un belge. Ça ne change pas grand chose ^^

  6. Fazer says:

    I believe difficulty increases with each level, it’s reaches its peek at the last level, not the middle one. Look at how Versus maps are scored.

  7. Nicolas says:

    We always felt that the third map was the most difficult. The final in itself is not really difficult, much less difficult than most of the third maps IMO.

  8. iah says:

    Merci de vous investir autant, j’ai hâte de parcourir de long en large votre campagne, qui ( mes potes et moi ) nous fait salivé d’avance !

  9. MisterJ says:

    Vous dites que underground est plus longue que sewers mais ce n’est pas une raison selon moi de mettre 4 medic packs de plus. pour sewers, il me semble qu’il n’y en a qu’un de plus (dans un ambulance). avoir moins de medic packs force les joueurs a jouer en équipe.

    Vous avez remarquez que la ligne noire sur votre diagramme trace une montagne. I hate Moutains !

  10. Geoffroy says:

    Speak english please. This thread must be understandable to all ;)

    About underground: the different closed tests we’ve done showed that more than 4 medick pack could be necessary. But we’ll think about this point more seriously during the opened beta testing phases

  11. Yotho says:

    Je vous admire les gars !j’adore votre travail !

    Continuer ainsi

  12. Anonymous says:

    I really like what I see, but I hope you are also aware what makes versus maps difficult. It certainly isn’t claustrophobia. In fact even in co-op the open maps are usually more difficult. Also please don’t make health kits abundant in VS and in VS survivors should never start with tier 2 weapons.

  13. Anonymous says:

    Damn really looking forward for this… can’t wait to play it online with some friends…

  14. Anbrad says:

    Is this still coming out plz contact me over the coments about it im just wondering if its a finished but not released never to be or is in the progress Thanks

  15. Ahaha don’t worry! You’ll have a new soon ;)

  16. Zecomm says:

    There will be witches right?

  17. Nicolas says:

    Hm, I suppose.
    Why not ?