Thank you so much for playing! Several hours, wow... That's dedication :O Congratulations!
Regarding walls - the idea was to incorporate the "limited" theme in a way that wasn't just an inconvenience to the player. I thought the pressure and perhaps dread from dealing with the walls could really add up to the atmosphere, and am glad that people like it ^^
Oh, and don't worry about Hard for now, the only difference is the HP you get at start and after using the continue, not sure if I'm going to adjust enemies or patterns on normal/hard in the future. You already got a huge W, and I'm very glad that you enjoyed the game so much ^^