At times, it’s easy to see that Cyrano is a comedy; it’s outlandish, hilarious, and features clever verbal sparring and over-the-top wit.
At other times, it seems dark; there is death, thwarted love, revenge, etc. The thing to remember is that this dark stuff isn’t so tragic. Just look at Roxane’s depiction of getting through the enemy Spanish lines, or Cyrano’s absurdly grandiose speeches on his deathbed. These moments aren’t supposed to be tragic, but kinda comic in their exaggerations.