Very fun game, however after having played it a number of times the HUD has dissappeared for no apparent reason.

No health bar, armour status, ammo left. Nothing. Game still runs fine, but as you can imagine the loss of the HUD makes playing it impossible.

Any thoughts?

I think it might be a control button assignment. Try pressing F1 or the TAB key and see if it toggles the HUD.

Excellent, thank you muchly.