|Image from PopMatters|
It's not an overly metaphysical piece in the sense of coming to terms with the realities of human existence. It's more focused on the importance of failure, and why difficult roguelikes such as Spelunky incorporate death into their stories gracefully, albeit brutally. Simply put: the fact you start from scratch every time means your death is the end of a discrete story; a stand alone adventure with it's own arc of challenges and triumphs. There's no cognitive dissonance of having to reconcile "death" with some canonical in-game story (as is the case with most plot-driven games).
There are other ways of tackling this problem. Prince of Persia: The Sands of Time's "That's not how it really happened" voice overs after a failed jump come to mind as a particularly novel example. Spelunky takes a different approach by actively embracing every act as canon: everything you do is actually "how it happened." The beauty is that, thanks to the game's systems, you also know why it happened. Every death is the end of a story, but it's also a lesson (often a cruel one) for the next adventure. It's a dramatic death; an educational death; a good death.
Finally, I included a neat video of Derek Yu, Spelunky's creator, talking about and playing the game. It's still relatively rare to hear developers talk candidly about both the philosophies and logistics behind their games, and this good natured play session is well worth your time. It's also great to see Spelunky rise up thwart the very person who created it. For some reason, I take solace in the fact that Derek can get dispatched by the same traps that end my runs. Hearing his philosophy of experimentation, challenge, and iteration based on past failures is interesting; seeing it in action as his run is ended by the systems of his own creation is delightful.