An amazing game, but quite honestly, the whole element system appears... half thought out. Generally, fire weapons do LESS to enemies which channel fire, and MORE damage to those that channel ice. I try to think of it as Anti-fire, but for specific "Fire themed" gear, such as weapons with hilts with flames, makes it... strange. On the whole, the element system needs a rework.
An interesting note about the portals: They do, infact have a behind for backstabbing. By my experience, they spawn facing a random direction, and by circling them mashing the backstab key, you can find the "sweet spot", allowing the earlier portals to fall with ease.
You can press 1, 2 or 3 to switch weapons