Playing a rogue

[jevansau]

The Speed potion or haste self spell gives you +10 to speed. Base speed is 10, so if you have no additional sources of speed it does double your speed. If however you already had +10 from equipment it would only be taking you from 20 to 30 (so 50% more).

I believe hurt by an element means it takes double damage from that element.

[Pete Mack]

Hurt by an element means it takes 33% more damage. The big ones are Hydras and frost, and vampires (and some other undead) and fire.