Here's a bug report,
So, despite you having removed the timer modifier for bosses, the temporal hourglass is still obtainable and appears frequently despite being completely useless. Additionally, if you're in challenge mode, obtain the needle to acquire two soul hearts, and then collect the phoenix relic, whenever you die, you come back to life with 0 health and can play the game normally until you reach the next level. The moment you start said next level, you die. On seed 4324984313, you spawn with 0 health, and the level is glitched to where even when you clear all of the mines, you don't win. This might also happen on other seeds, but I'm not sure. Overall, pretty good game.