At present there only 6 possible operation modifiers. 2 of these are Automaton exclusive while 2 are Terminid exclusive. The other two can spawn for both factions. Super Helldive difficulty always has 2 modifiers, so you will have to pick two of the four modifiers available for your run UNLESS the planet is currently part of a defense campaign where all missions will have 0 modifiers. Do note that certain missions are not available during defense campaigns
Missions on planets under siege have no modifers, but their availability is limited by real time constraints as well as the fact that certain missions are not available during defense campaigns.
What it does: Stratagem call-in time increased by 50%
Select this modifier for run?: NO
Effect on speedrun: Probably the most damaging modifier for a speedrun, avoid it at all costs! The extraction counts as a stratagem and will be increased from the default 2 minutes to 3 minutes (without pilot booster). This means up to an entire extra minute will be added to your run which you can do nothing about. Additionally, the time spent waiting for stratagems to activate will be increased which can add time to your run in cases such as Command Bunkers where you have to wait extra time for a 380. Eagle Airstrike has an additional 2 seconds call in time added by this modifier.
What it does: Stratagem cooldown increased by 25%
Select this modifier for run?: Yes
Effect on speedrun: Usually neglible so long as you budget your red stratagems properly. Virtually no effect on blue stratagems other than EATs and Commando. All multiplayer runs are short enough (less than 10 minutes) to the point where higher cooldowns don't make a difference. However, repeatedly using Eagles will be negatively impacted somewhat (2 more seconds waiting in between uses) which can add a few seconds onto certain outpost clears.
The best modifiers for Automaton missions are Poor Intel and Orbital Fluctations, although gunship patrols can potentially be used in place of either. Never pick Complex Stratagem Plotting if you can help it!
What it does: Large groups of gunships spawn at edges of map and move across map to the other side in a patrol pattern. Patrols have less gunships in singleplayer
Select this modifier for run?: Maybe, but have a plan to deal with them
Effect on speedrun: Extremely threatening and lethal, but their impact on time can be mitigated through planning and/or teamwork. Can cost you a lot of time or resets due to how many ships spawn (up to 4 in multiplayer, as many as one wave from a double gunship fab).
In order to deal with these effectively, all players should call out patrols when they see them. This callout should include location, number of ships, and direction of travel. Next, the team must decide whether to avoid or engage the patrol. If engaging, at least 2 players should gang up on the patrol otherwise you run the risk of one player being killed or bogged down in a lengthy engagement. Their high elevation should allow multiple players to destroy the patrol even when split up given the long sightlines.
https://youtu.be/cjd5N30cnFM?t=570
If avoiding, stay out of the red searchlight to avoid detection and avoid making noise or using red stratagems in the flight path, as this will send the gunships into search mode. In this clip here you can see I am right underneath the gunship but remain undetected due to not making any noise and staying out of the searchlight.
What it does: hides exact location of objectives on map, instead displaying a radius similar to the eliminate X enemy mission type
Select this modifier for run?: YES
Effect on speedrun: Basically a freebie if you pre scout and annotate a map with the real location of objectives. Not that impactful even without pre scouting as true objective locations are easily determined by just looking at structures either on the map or environment. Red splotches and pre-revealed sides on the preview also have inaccurate placement, but display normally after drop
The best modifiers for terminid runs are usually atmospheric spores and orbital fluctuations.
What it does: map obscured by yellow hazy spore effect, hiding side objectives, POIs, and bug outposts until they are discovered. can be difficult to view terrain outline as well, but not impossible
Select this modifier for run?: Yes (if pre-scouting)
Effect on speedrun: Basically the inverse of Poor Intel (sides hidden instead of main). Freebie with pre-scouting, but unlike poor intel is very damaging to non pre-scouted runs since it is much harder to discover all the sides and outposts compared to main objectives, and there is no hints given whatsoever as to their location. Worth noting that it is possible to create map markers in game for outposts even though the icon is hidden if you simply click where the outpost would be after discovered. Icon is fully displayed for sides so no workaround needed for creating map markers. Also note that this modifier disables radar and pings from scout armor!
What it does: large groups of shriekers spawn at edges of map and patrol to the other side of map in a similar manner as gunship patrols
Select this modifier for run: Yes? If your primary weapon can handle them
Effect on speedrun: pushovers for certain primaries, but can be deadly for others or in certain situations. Can also repeatedly flinch you off of terminals which can be very annoying and lose you time. Not as impactful as gunship patrols, but similar to that modifier just selecting cooldowns is probably easier to deal with overall
Helldivers Wiki for some assets and information
https://helldivers.wiki.gg/wiki/Boosters