Prepare an 8×8-inch baking dish with parchment paper, leaving some overhang for easy lifting.
In a medium saucepan over low heat, melt dark chocolate chips, sweetened condensed milk, and butter, stirring constantly until smooth and glossy. Avoid high heat to prevent scorching.
Remove from heat and mix in vanilla and almond extract until fully combined.
Stir in cherry gelatin powder until dissolved, letting the mixture turn a rich, dark red.
Fold in chopped maraschino cherries. Add a drop or two of red gel food coloring for a bloodier swirl, if desired.
Pour the fudge into the prepared pan, smooth the surface, and press a few cherry halves on top.
Refrigerate for about 2 hours or until firm. Lift out using the parchment paper, slice into 36 squares, and serve chilled or slightly softened.