Armor should actually block a hit

Guard was starting to feel like a slightly different health bar. If I had one Guard and took a five-damage hit, losing four health didn't really give me the feeling of having blocked anything.

Now, that hit breaks the remaining Guard and stops there. The same rule applies to enemy armor. A tiny bit of protection can save you from a big hit, but it also means an armored Knight deserves a little more respect. Guard that hasn't been used stays with you until something breaks it.

Armor removal has a useful fallback too. Any removal left over after dealing with the target's armor turns into damage at half strength, rounded down. That keeps an armor-breaking upgrade from feeling completely wasted when the next fight happens to contain enemies with no armor.