Exterminator achievement in Halo MCC


Halo 3: Beat the par score on Floodgate.

1 guideOnline/OfflineSingle PlayerCooperative

How to unlock the Exterminator achievement

  • Wicked JeiWicked Jei529,248
    23 Nov 2014 23 Nov 2014 16 Apr 2017
    45 1 12
    The par score for Floodgate is 25,000. To get a nice multiplier of 3.00x, you'll have to beat the level in under 15 minutes. It's a short level and can be run within that time even if you fight every battle. Put your setting to competitive score under options before starting the game so that you can keep an eye on your score and time while playing.

    Heroic difficulty with a few skulls on will give you multiplier you need to achieve 25,000.
    Getting kills without dying builds up your killstreak and earns you more points. Multikills also give you slightly more points.

    This entire level has only flood enemies, who are not too threatening even on heroic.


    Catch - enemies throw more grenades. Doesn't affect the flood.

    Tough Luck - enemies will dodge more.

    Fog - No motion sensor. You can probably get away with not using this skull if you find the lack of motion sensor annoying against flood.

    Iron - Dying restarts the level. If you die, save and quit immediately, then resume from the last checkpoint to keep score intact. Doing this will reset your killstreak, however, meaning you'll get less points per kill until you build it back up again! It seems a recent patch causes the save and quit method to invalidate the achievement.


    Dual plasma rifles are your friends and they're everywhere. SMGs aren't too bad, either. Try to hit flood where the tentacles come out of their chest, it's their critical point.

    Grab the gravity hammer on the dead chieftain at the beginning and use it against the first few swarms of flood.

    Don't kill any marines unless they fully transform into flood. You'll lose points otherwise.

    Don't bother with the flamethrower unless you're very, very careful.

    The energy sword is excellent for the pure flood. It's a one-hit-kill on the flood tank forms. Avoid getting swarmed or you will die. Bubble shield and Regen fields can help take out groups when you have a sword.

    Stick to cover when fighting pure flood ranged forms because they're very precise and will knock out your shields quick.

    You can use the turret on the level to take out some of the flood pure forms quickly.

    WATCH THE FULL END CUTSCENE. Skipping ending cutscenes on any level when going for par score may cause the achievements to not unlock.

    I was able to get about 32,000 with 3 minutes to spare. You've got a nice bit of room for error.

    Unfortunately, the par score achievements in this game be can stubborn about unlocking. Personally, I had to play through the final level several times for the achievement to unlock. You may want to wait for a patch if you don't feel like testing your luck.
    Showing most recent comments. View all comments.
    dingleinguswas able to get this on Heroic with 1.74x scoring skulls in 13:34. wasn't too hard - just kept running/killing, pausing only when i needed shield.
    Posted by dingleingus on 31 Jan 15 at 08:06
    yollom69Iron may be problematic now the Save/Quit Resume appears to have been removed in recent updates. Just completed with a score > 25k with Iron, 1 death, Save/Quit. no achievement angry
    Posted by yollom69 on 18 Mar 15 at 01:06
    TheBigBBI thought it was better to also turn on the famine skull. With catch skull on, the elites throw tons of plasma grenades, enough to make it very random and dangerous to lead the charge at the end of the mission. It was easy to get enough ammo with famine, and it gives you so much leeway that you don't need to worry about anything.
    Posted by TheBigBB on 11 Jun 15 at 07:07
    bryan dot exeYou weren't kidding about the final cutscene. Fml.
    Posted by bryan dot exe on 21 Jun 15 at 19:35
    The Dethdefyer@Dragonborn Gear - Your solution was perfect! With the BR I was able to take out Flood so fast. I think I hit par only 3 minutes into the level and ending up with nearly 50,000 points for the entire level - and within par time. Definitely try this method if you're struggling.
    Posted by The Dethdefyer on 10 Jul 15 at 18:45
    Vr EnglishI agree with yollom, I think if you use the iron skull it invalidates the data.
    Posted by Vr English on 01 Apr 17 at 15:12
    DELT4 UK@Dragonborn Gear - I would agree this is an even better solution - reason being is that you can kill the enemies before your elites get chance. It's also better if your elites die because they throw grenades at you!
    Posted by DELT4 UK on 09 May 17 at 18:25
    Tozi TiberiusYou can no longer worry about skipping the ending cinematic. Played on heroic with famine instead of catch, iron on, skipped final cutscene, and it popped no problem.
    Posted by Tozi Tiberius on 01 Dec 19 at 17:01
    The JoelstrBlack eye skull helped me out a lot. Melee the flood with hammer will give you your shields back and let them group around you and you can get big kill streaks
    Posted by The Joelstr on 20 Jul 20 at 03:05
    DesPawsI don't think use of save/quit of the Iron Skull has been patched out. I have still used it. What I do think is happening is there is a bug in Halo 3 where sometimes "Competitive Score" get's changed to one of the other options, and then you don't get credit for your score at the end of the mission. I've seen this happen on both "save/quit" after a death, standard "save / quit" to enable resumption of a session, and I've seen it happen on completion of a mission, get my "par score" achievement, and the next level will load without "competitive scoring" enabled, even though all settings were left "as is". It took me a few failures to get par score achievements and just general playing around before I noticed what was actually going on.

    The only way I've found to correct it is to save/quit, re-select the mission with something else enabled (such as "competitive time"), load the mission, save/quit, re-select mission with "competitive score", and start over.

    Again, I've seen this setting get flipped on standard things like a new mission load, or standard save/quit, not just on a "death save/quit" with iron skull on, so I'm not convinced it's a "patch" of a perceived Iron Skull exploit. Each time "competitive scoring" is still set in the "settings" menu when you go out and look, but in game the scoring window is obviously set to something else.
    Posted by DesPaws on 01 Nov 20 at 18:53
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