Completed few levels, so far game is really good but i have few suggestions.
-framerate is very poor, please enable smooth 60 frames per second
-better automap, with map hotkey showing all level, also make doors visible in map(colors too)
-better damage indicator, optional subtle directional arrow or something
-wierd sound balance, i almost cant hear hero voice
-quicksave feature, yes i know, game has lives system but maybe new difficulty with normal saving?