One of the areas of confusion about Lone Spelunker seems to revolve around the fact that it is a side-view game instead of a top-down view. This, combined with the fact that you can jump and fall, seems to lead people to wonder if the game is a "platformer".
Well, just to allay the confusion: No, it's not a platformer. This is not a game like Rogue Legacy where your "twitch" skills play a fundamental difference in how you will succeed in the game. There are a few places where there are real-time effects - most notably falling - but for the most part, this is straight up "press the key once to move one tile in that direction" type movement we're talking about here.
Which isn't to say that a platformer with the conceits of this game wouldn't be fun. It probably would be. Running through caves, swinging on ropes, etc. would probably be a blast.
But in terms of the tone I'm trying to bring, I just don't think the standard platformer play style would support the sense of wonder and deliberate exploration. If you could "run n jump" your way through the caves, it would all pass by rather quickly, and the discoveries you make wouldn't feel earned. The slower pace, forcing you to pay attention to safety and planning your routes, seems to have the right feel for evoking the sport of spelunking.