This page of the XCOM Chimera Squad guide has all the information on the available difficulty levels. You will check the available difficulty levels and additional modes that make the game even more difficult like e.g. Ironman mode.
XCOM: Chimera Squad has 4 main difficulty levels:
- Story - It can be treated as a story mode in which opponents don't pose a big challenge. This is an optimum choice for those who are playing the XCOM series for the first time, and for those who are only interested in experiencing the story.
- Normal - The standard difficulty level and recommended choice for the first playthrough. The game offers a balanced challenge that shouldn't cause much frustration.
- Expert - Fights with enemies are much more challenging. This increases the chance that someone on the team can get knocked to the ground or that you will need to repeat the mission.
- Impossible - The highest difficulty level is very demanding. We definitely don't recommend choosing this mode if you haven't already completed the campaign and familiarized yourself with the turn-based combat system.
Regardless of the main difficulty level chosen, you can also enable or change additional difficulty modifiers. They are:
- Ironman - manual saves are unavailable in this mode. You only have to rely on a single autosave. Fortunately, if you fail a mission, you will be able to replay it.
- Hardcore - This is the most extreme difficulty level. A defeat in a mission automatically ends the entire campaign - the saves get deleted forcing you to play the game from the beginning.
- Extended City Anarchy - this facilitation is related to the level of anarchy in City 31. It gives you5 extra points to the anarchy bar. As a result, the city can "survive" for longer before the anarchy reigns - this will lead to game over.
- Tutorial - You can disable all tutorials. It is best to leave them on for your initial playthrough, as XCOM Chimera Squad has many completely new or changed mechanics.
- Heal Between Encounters - Encounters are separate battles played as part of a single mission. A single mission can consist of 1-3 battles. You can allow team members to be fully healed after a battle, recover only half of their HP, or have the healing disabled. The last option is, of course, the most difficult - if you play a longer mission, you will have to complete it with the limited health points and med kits.
An important feature of XCOM Chimera Squad is that you can change the main difficulty level during a playthrough. To do this, you need to select Change Difficulty option in the pause menu. The list of available difficulty settings doesn't include Ironman and Hardcore levels nor anarchy bar extension.
Note - The difficulty will change in the next mission. You can't cheat the game and make the current battle easier.