Is cave story+ a dark game?

There's some trolling here, but that's how the community goes at this rate.
To answer your question, Cave Story+ isn't really a dark game. You have to look in to it to find some dark parts.
There's a couple character deaths, so this game might be a stretch, as you said that character deaths are very harsh on you. (To be fair though, other people get tripped up on them so don't feel bad for feeling down for a while.)

Spoiler

You can actually skip all but 2 character deaths, but you need to know what you're doing, as you have to do some complex things to prevent some deaths.

 

are you trying to troll me?

Nah, we're just assholes.

 

Nah, we're just assholes.

Yeah that's what I thought, I wanted to be friendly though dawg.

 

Anyhow, CS is mostly bright and cheerful with some very slightly dark moments in the middle. When death occurs the game doesn't show blood or draw things out. Just remember to ignore Booster when he falls and to look for a sparkling object to the bottom-right after the core fight and two characters will be saved.

 

Play King's Story instead

Yeah! King's Story is the delightfully cheery tale of King, a Mimiga from the classic Cave Story. It's all about how King plays hide and seek with friends. He trips down a stair and knocks himself out, and his friends get lost. He then saves each one from a surface robot and they all live happily ever after. King returns home with his Mimiga friends, and his new robot friends!
This mod was made by Noxid, thank him later!
Here's the link to the download:
http://www.mediafire.com/download/b7f95z37t32a5l6/KS+0105.zip

 

If you don't like blood or characters dying then ignore everyone here and don't play King's Story. Everyone who recommended it on family friendly values was being sarcastic.

 

It's definitely a dark game. Without giving too much away, characters do die, which is sad, but it's often the manner in which they die that's really heartbreaking. Even more than that, though, things just generally don't go well for the protagonists. Unless you get the best ending, there's this pervasive sense of hopelessness that kicks in about halfway through. And that's quite surprising, given the bright aesthetic and initially cheerful music. So for the type of game that it is, it's on the darker end of the spectrum.

 

At times.. yes it is.

 

There are only some friends of you in the game that need to die without any exception (and with any i mean any but a mod). Be sure to get the best ending, and its only 2.