it was my first Colosseu and I didn't know any rules about, so for first 24 hour I miss more than half fights,
so I recommend that put the information somewhere (maybe at home page put in info icon or help button)
and I saw some items for first time too (even if I saw before maybe forgot those!) information about them is appear just when we take it (at achivement Items) not on Colosseums map (or maybe show the list of Items by name and abilities at somewhere else and put in info icon)