You can, controls can be configured in game and through the launcher. Traps and most other things can also be brought up with hotkeys and other menus in the game. After playing, the middle mouse can even be somewhat slower than you'd like for certain things.
maybe if you can change the button mapping in the full game id consider buying it. its not too expensive but if you cant change the mapping, then i cant play the game :/
Regarding online play... You weren't kidding, playing with others really does show you a few things... Particularly that 9 out of 10 people have their head up their ass and will do everything in their power to use up DU on traps that do next to nothing in that location. Walls and barricades in places where nothing would be able to reach, using traps as a primary defense, lightning auras near lightning towers, push barricades and slicers far in front of other traps usually by doors instead of making use of choke points. Oh, and games where someone who is of the same class decides to scrap all the stuff you built and replace it with their own shitty versions so that they get more kills. I mean, except for the last one, it's not technically wrong sometimes, but is just inefficient at best, pure stupidity at worst.
That's not to say that a huntress cannot be decent with traps, but seriously... If playing campaign on medium difficulty, where a spot already has a fireball tower, lightning tower, and a barricade... Selling traps from another area to free up DU so you can add proximity mines to an area already covered perfectly. It's just... Stupid. If they were setup earlier on the path, and the game was survival so that the trap would be taking out some of the initial runners (dark elf warriors for instance), it might make sense. Dropping a choking trap where an ensnare aura already is... Useless... Dropping a flame trap where a lightning aura already is and there's no other defense... Damn useful. Dropping traps right in front of a primary chokepoint that is already well covered... stupid... Dropping traps in a spot that isn't quite so well covered to buy time so that stronger defenses can be made... game saver. I mean, it's what the class is really designed for. I mean, I'm not so good on my huntress either, but atleast I know my damn role. /rant