I noticed that some attacks don't benefit from vulnerable, like fatal frame. Also, idk why the game crashed. Maybe it's because the last card I played last turn was dat fatal frame, so death cancel got confused.

java.lang.NullPointerException
at sumireko.cards.skill.DeathCancelCard.use(DeathCancelCard.java:77)
at com.megacrit.cardcrawl.characters.AbstractPlayer.useCard(AbstractPlayer.java:1698)
at com.megacrit.cardcrawl.actions.GameActionManager.getNextAction(GameActionManager.java:359)
at com.megacrit.cardcrawl.actions.GameActionManager.update(GameActionManager.java:175)
at com.megacrit.cardcrawl.rooms.AbstractRoom.update(AbstractRoom.java:325)
at com.megacrit.cardcrawl.dungeons.AbstractDungeon.update(AbstractDungeon.java:2532)
at com.megacrit.cardcrawl.core.CardCrawlGame.update(CardCrawlGame.java:876)
at com.megacrit.cardcrawl.core.CardCrawlGame.render(CardCrawlGame.java:423)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126)

Yup, Fatal Frame removes your Charge, and there was an unchecked access to the player's Charge in Death Cancel. I can't believe I never came across that.
It'll be fixed in the next update.

As for Fatal Frame's damage (and other cards that refer to specific numbers), they are meant to deal fixed damage.
I guess card's like Body Slam also refer to an outside number and do scale with Strength, though.
I'll think about it again, and if I don't change it, explain on the card that the numbers are not affected by modifiers.

Apprentice Occultist challenge run modifier makes strikes not work. I believe it is only supposed to make telekinesis attacks into skills.

Yeah, Strikes are supposed to work like normal. I'll check what I broke, though the Strike files themselves are correct, for better or for worse.

I think nothing with a target works, including skills like Perfect Possession.

Thanks for checking!
I found the cause. Turns out, a "fix" I put in to make it so that cards don't regain their targeting after reloading broke all other cards. Not sure how that slipped through.
I'll upload a proper fix soon (but I'll first make sure my new fix didn't break anything this time.)

Strikes aren't tagged as basic strikes, which affects some events and other mods.

That's odd. They are tagged as Strike and Starter_Strike.
AFAIK Pandora's Box checks for the Starter_Strike tag as well, and that relic works.
The Ancient Writing event (upgrade all Basic Strikes and Defends) also works for me.
Which event was it that failed for you?

I investigated more thoroughly, and the issue I was experiencing was due to another mod, but only showed up for this one due to the fact that there's no basic rarity attack cards of cost 1 with a positive damage value (they all use telekinesis). So nothing to fix on your end, sorry for the confusion.

That's a rather specific requirement. :D
No worries, glad that everything works as intended.

Hydrokinesis upgrade doesn't do anything

Hydrokinesis does not exhaust on upgrade.

Apprentice Occultist telekinesis seems to be affected by attack modifiers like strength, weakness and triggers stuff like thorns and reflect damage. I'm not sure if it is supposed to do that.

Apprentice Occultist still has some issues which makes strikes not work sometimes, though at least it works sometimes. I'm not sure what causes it to change into a state where the strikes don't work.

Apprentice Occultist says that telekinesis is not affected by damage altering effects, but I think it is affected by - strength.