A few tweaks and fixes based on a falexxx1 test from earlier today.
- Don't decrease drop rate for hard and very hard difficulties. 25% on every difficulty now.
- Lessen the rate at which enemy weapon and magic levels increase for hard difficulty. This should make it notably less difficult.
- Fix an issue where in one out of every 30-40 ROMs the Mana Beast door would get overwritten and end up taking you back to an old floor.