Lovely
Lovely game and atmosphere. A work or art. The wall jumping could have been explained better imho, it took me a very long while to figure it out. The trick is: the down arrow should be kept pressed, don't release it until making the actual jump, while the left or right arrow (depending on the side of the wall) must be used all the time to adjust your position so that you're not going downwards while holding the down key but at the same time don't go too high so that your ship is positioned such that it'll jump upwards when finally releasing the down key.