The X or Extreme missions are a special set of operations that are unlocked in Trauma Center games after completing all of the standard missions on any difficulty. These missions always are focused around a single GUILT or Stigma strain that is exceptionally more powerful than when encountered on any regular mission. These missions are listed under the "Extreme" difficulty.
Major Differences - GUILT[]
Kyriaki[]
- Kyriaki attack with much higher frequency
- Lacerations caused will deal much more damage
- More Kyriaki bodies will be present
- If on Under the Knife 2: the number of Kyriaki pupas will increase each time the Queen Kyriaki hides into the organ after it is lasered. (2,2,3,3,4,5)
- Vitals will drop much faster
- Increased HP
Deftera[]
- Tumors will drop vitals much faster
- Tumors will spawn polyps faster
- Deftera will cause more vital damage when two of the same color Deftera combine
- Deftera will cause hemorrhaging (Second Opinion only)
Triti[]
- Triti layout will be much less conducive to removal
- Purple sections will deal dramatically more damage
- Thorns will vaporize more often
- Vapor will move faster
Tetarti[]
- Diverticula will grow faster
- Tetarti will move faster
- Less time to inject all three with antigen
- Poison mist will do more damage
Pempti[]
- There will be less time between each attack
- Attacking bodies will be more resilient to damage
- Polyps and lacerations will deal more damage
- Pempti sometimes sends out two waves of attacking bodies in succession
- In Under the Knife 2, Pempti core resilience will be slightly unevenly distributed
Paraskevi[]
- Vitals will be maxed at 50 (Second Opinion only)
- Dissecting a Paraskevi body will deal 30 damage (Second Opinion only)
- Paraskevi will attempt to move to next organ earlier
Savato[]
- Nest will turn red significantly faster
- Savato will spawn more mini-Savato bodies with its attacks
- Attacks will occur with higher frequency
- Laser will need to be applied much longer than normal during the second phase
- Mutated Savato
Major Differences - Stigma[]
Cheir[]
- More Cheir bodies will attack at once
- Cheir will attempt to create large lacerations and tumors, as well as the normal lacerations
Soma[]
- Small tissues will harden faster
- Soma will spawn more red and blue polyps
- All polyps and hardened tissue will deal significantly more damage
Ops[]
- Smaller bodies will fire nutrients more frequently
- Tumors will deal massive damage if detonated
- Ops will take more laser hits to defeat
- Tumors spawn much more often
- Ops cores splitting after to 2 laser incinerations
Onyx[]
- Onyx will not wait as long to attack (You've got approximately 7 seconds to find Onyx)
- Letting Onyx attack will deal 70 vital damage
- Venom in third phase will drain vitals much faster
Brachion[]
- Venom will move through the grapplers much more quickly
- If the venom is allowed to reach the grapplers, it will deal much more damage
- Grapplers need to be removed two additional times: there are 21 of them to be extracted instead of 14 (3,3,3,4,4,4 instead of 3,3,4,4)
Cardia[]
- Red tiles will reduce max vitals by much more
- Cardia will attempt to detonate tumors in the second phase more quickly
- More laser hits will be required to finish it off
Major Differences - Neo-GUILT[]
Nous[]
- Amount of tumors will increase (Last stand is 6 spore tumors, instead of 5)
- Smaller window of time to treat and remove tumors before Nous dives
- Instead of 30 vital loss per tumor when a wrong tumor is touched, the vitals drop by 65 per tumor
Bythos[]
- More lacerations at the pre-GUILT stage (8 instead of 4)
- Core has to be removed 6 times
- Core spores move faster
- Greater vital damage if a spore or shard is touched (50 vital damage)
Sige[]
- Hematocelae are created more frequently
- Sige will move faster
- More clones created by Sige
- Pus is formed very fast and will cause severe damage
Aletheia[]
- Vitals will drop much faster
- Smaller window of time to inject antibiotic into Aletheia
- Blood veins will alternate faster