Arknights: Main Theme Episode Tuning: New Level Difficulties - Explained!

With Episode 10 - Shatterpoint there will be a change in the difficulty levels available for each Main Theme stage.  Currently each stage has two difficulty levels: normal and challenge mode. With Episode 10 there will three difficulty levels: easy, normal, and hard.

Let's look at Stage 10-17 to see examples of the differences

Easy mode exists so new players, or players with undeveloped rosters can still clear stages to continue the story.

There will be buffs to make it easier for players to clear:

and there will be some small first clear rewards:

However, there will be no regular drops at this difficulty so it cannot be farmed.

Other things to note:

• This difficulty does not cost Sanity.
• Completing this difficulty only unlocks the Easy difficulty for the next stage.

This difficulty is basically the equivalent to the current normal difficulty.  First clear rewards 1 OP and the stage can be farmed.

For Hard mode, a set of conditions are applied to increase the difficulty, similar to the current Challenge modes:

All and/or specific enemies can receive buffs:

And even the number of enemies and the map itself can change!

Hard mode awards 1 OP and also has material drops, though it seems likely the rates are the same as Normal mode (not enough data exists to be conclusive)

Players have the option to clear Hard-mode first and, upon successful completion, receive rewards from all easier difficulties, but the sanity required is the sum of all individual runs.

• Episode 9 will also receive the difficulty level adjustments.  Players that have already cleared Episode 9 stages will receive the "Easy" mode rewards automatically.