After watching some outdated playthroughs, I feel like Ame could do the following to make the game harder:
- Remove Common Candies, or at least make them insanely expensive/scarce
- Give earlier Gym Leaders their Hyper Potions back
- Give Shelly her Shell Smash Crustle
- Change the game settings from "Shift" to "Set" so the player can't pre-switch between each Pokémon (srsly, how is that fair?)
- Implement a system similar to the one on Pokémon Showdown that makes a move fail if it would cause a violation of a certain set of clauses (This would mostly be used to prevent players from mindlessly spamming sleep moves)
- Remove Torchic's, Chimchar's, and possibly Froakie's hidden abilities from the starter Pokémon
I can't count the number of times I've seen someone go, "Oh no I'm losing this Gym battle, guess I'll send out my Compoundeyes Butterfree and put all your stuff to sleep!" or "Hmm, I COULD try to find a creative way to beat Samson, orrrrrr I could just use my Speed Boost Blaziken to sweep an entire team that's 10+ levels higher than mine."