Very strange keyboard issue in Lara Croft and the Guardian of Light

[LookingGlass]

So, I'm playing the demo for Lara Croft and the Guardian of Light for the first time and I'm having a weird issue.

Basically, I cannot jump whilst holding the S and A keys (so I can't jump diagonally down and left) or whilst holding the S and D keys (so I can't jump diagonally down and right).

Now:
1. I can jump directly down (S key only) or up, or diagonally up (W+A or W+D).

2. In fact, I can jump diagonally down if I use the down arrow key and A and D... or any other key except S for down.

I've never seen anything quite like this before. I'm wondering if anyone's ever had a similar problem or has any theories. Google didn't help me.

I'm playing it through Steam and using 64-bit Windows 7 Professional on a desktop PC with a USB keyboard, if any of that makes a difference.

 

[LookingGlass]

I found a few entires in the steam forums... but no solutions. Seems to be a bug in the game.

I found a way to use my PS3 controller though, and that was much better anyway.

 

[Chesamo]

Some keyboards are designed so that certain key combinations don't work properly -- it's been a huge problem in the Stepmania community (or whatever's left of it) for a while. If you can, try a PS/2 keyboard (the old round-plug style, not Playstation 2) and see how that goes.

This is from my own experience, by the way. I don't have any facts or figures to back it up.