Looks a little flat...
Okay, so this gauntlet seems to have a lot going for it in the way of forearm protection and finger protection, but there's nothing covering the back of the hand, except for a piece of rubber, which looks like it would be better serving the palm of your hand, to aid with grip, for example.
I know that there can be issues with providing some sort of robust padding there, as I wear heavily padded gloves while playing cricket. You've got a lot of room for manoeuvre, as the back of the hand doesn't move that much , except maybe at the joint of the wrist, which I'm sure you could work around. The two ways to look at going are extensions of the finger detail, or just a massive pad across the back of the hand.
As far as the aesthetics of the piece look, you may wish to consider increasing the curvature of the guard around the arm, as opposed to leaving a piece which looks like a triangular board strapped across the arm. Continuing your angular theme, you can certainly afford to add a little more detail to the top of the arm-guard, especially when you consider the fact that there is a nasty array of spikes on either side, which can be used as improvised weapons (or possibly that was your intention in the first place?)
[Review Request Club]