The game I’m working on is a 3d RPG with active/none turn based combat mode. But I have run into some problems with designing one of the key features, used mainly in combat. The main problem I have is that I have trouble with the numbers of buttons required. In combat, you have buttons for movement, dogging, duck, jumping, attacking, pending camera (mouse?), and then comes the problem. I shall have a list with special attacks, that the player choice from. That list will require 6 buttons, one for getting the list up, two for choosing up or down, two for changing page (not enough space on one side for all the attacks) and the last one for selecting attack. Or a quick choosing list that will require 13 buttons, the 0-9 buttons, two buttons for changing page and one for select attack. So fare it don’t seen to be much problem. But the problems are that when the player has that list up, the battle continues. So I must use other buttons then the already used. With what I have listed, the player will have to use 16 buttons (+mouse?). And if I go for the quick choosing option, the player will have to use 23 buttons (+mouse?). Is that realistic, or is it to much to keep track of?

I'd say keep the number of buttons as low as possible. Shoot for the six button scheme.

If the battle continues while the list is up, you may have to suspend the updates for other elements of the battle. Or maybe simply rework your interface design.

The first thing I would suggest is the use of a "radial" mouse controlled menu, like the one seen in Battlefield 2 or Neverwinter Nights - this can have a huge number of options when combined with multiple context sensitive rings, and if it works in a fast paced game like Battlefield 2, then it should work for you.

The other option is to just not worry about it. Have you seen anyone play World of Warcraft? The amount of crap on screen plus hotkey combinations is just amazing (especially with some of the interface mods you can download) and the players of that game don’t seem to mind.

You could try having keys that change what other buttons do when you hold them. For instance have a "special" key that once held down alters the attack, dodge etc. buttons to become special attacks. It can become a bit confusing, but if you design it intuitively, so that similar attacks use the same button, it should be ok. With a controller this tactic works wonders (using the shoulder triggers to alter the main button functions), but I'm not sure how it would work with keyboard and mouse. If you're using WASD for movement, then the shift, ctrl, alt and space buttons are all in close proximity, so holding these could alter the mouse buttons for instance. Potentially you have five buttons on the mouse (left, right, middle, middle up and middle down, though the up and down buttons might be dodgy) so with the shift, ctrl, alt and space buttons you have twenty five triggers (more if you include multiple triggers like crtl + alt + left mouse or something).

I'm sure you can figure something out. Bringing up a list during a real time battle is surely the last thing you want.