itch.io

Now that I think of it, yeah, underground appears to be the only place I can't seem to use my items.

Sure, here's a video:
https://imgur.com/a/GKJZpqx
I feel like I'm doing what I've done with the rest of the spots where I could use items; hit Z in order to check the spot, make sure the item I want to use is in my inventory, then press Enter.

In this case, I'm pressing Z to make sure I'm in the right spot with the plant, and then I'm pressing Enter to use my item, with nothing happening.  Then I switch to the candle, and then I'm pressing Z again to make sure I'm in the right spot, and then I press Enter to use the item.

I also found that I can press enter outside of the caves in order to get dialog about using the candle/water, but using items inside the cave doesn't seem to work for me outright.

Of course, there is an 11/10 chance I'm in the wrong spot and that I'm doing it wrong, in which case, terribly sorry about this whole thing, but I can't figure out where else I might need to go in order to use these items.

Would you happen to know of a way I could export my save? If so, I can try sending it over to you. 

I too appear to be having this issue. I can certainly interact with the thing I should be able to use two items on underground by hitting Z, but selecting either item in the inventory and hitting enter in the same spot doesn't seem to do anything.