I'm looking for violent 2D platforming game from 1990s

Hi all, I just spent over an hour googling it and failed, so hopefully some of the older folks here will remember. I'm looking for 2D platforming/puzzle PC game from 1990s. This is what I remember:

-The hero is a little boy and in the end, the entire game is revealed to be his playground fantasy.

-His main weapon is what would be called "lighthing gun" today, it fires continuously like in Quake.

-Later he can shoot fireballs from his hands and can also "charge up" them to kill tougher enemies.

-He can aim the weapons in 45 degree increments.

-The game is uncharacteristically violent for the genre, enemies rip the boy apart, break his spine etc.

-At one point a big enemy swallows him, but he shoots his way out of his stomach.

Thanks!

Do you by any chance mean "Heart of Darkness"?

Yes, that's it, thanks!

That game lifted nightmares on me as a 9 year old. Terrifying. Why did i play this.