Need indicators or a map. I know you can buy a compass in game, but the chances of it showing up are far too low. Have you ever played Doom, Eye of the Beholder, Castle Wolfenstein, Hexen, or even Maze? These games were are nonlinear first-person perspective games. Because of how elaborate these maps were with dozens of corridors, rooms, switches, and keys; the makers of these games implemented maps or compasses that didn't require finding them or buying them.
It was a way to balance between difficulty and ease while still providing for player exploration. These developers understood that with so many places to explore this was a necessity. Now, you could compare any of the Legend of Zelda games to this, but those games were far less complicated to traverse. (Exception the water levels.)
Another issue is the lack of item input. I didn't quite get the use of the crosses and tried using them to block ghosts. It seemed only intelligent that they could be a way to repel or destroy spirits, but then the utter uselessness of this item came into play. It was for tombs. Then going to the shops the items obtainable were far too random. I've never played a game where every item for sale is random.
Now I've read another review where you responded saying that the crosses were intentionally useless... DON'T DO THAT. As a developer, you shouldn't start implementing useless items UNLESS enough completely necessary items. That means grapple hooks, throwing knives, drills, lanterns. The point of a useless item isn't so it is more likely to get it, it is so that out of pure coincidence you obtain the thing and say "Well this is just fantastic, like I wanted this."
So overall I think the game has too many random elements which cheapen the experience. No one wants to play a game where the items are uncertain. And I honestly can't think of anything good because there were no "OMG, I just did that!" moments and no "Ahh sweet!" moments. The game felt far too generic.
So after saying all that I realize you derived inspiration from the game Spelunky. I'd like some feedback on what your development process was like and why you made some of the decisions you did. I don't want to put you on the defensive, but it would be nice if you explain some interesting dev choices or where you got your theme to the NG community.