Fair enough. This is why I didn't rate yet. :D
Is there a reason you can't have, like... I don't know... space, enter, X button on an Xbox controller, and left click all do the same thing? All the different buttons somebody is likely going to randomly try when they're new and they don't know what's going on.
Better yet, make it like Caves for android, except the mouse click does what a finger tap does in that game-- clicking a tile makes you pathfind to that tile. Clicking a monster on a tile makes you pathfind to it and attack it. Clicking an item makes you pathfind to that item and pick it up. It's the easiest control system for someone on a computer. Literally the default reaction to anything in a web browser is to try and click on it.
Manage to get touch input working the same way, and now you're servicing the gut instincts of everybody browsing itch from their phones, too.
That said, I'll use space for now. See how this game is. Sorry if I missed where it said that in-game.