Prism is beaten
So my online friend in Mindustry Tower Defense game, "Rafastian", beat the prism and showed me this image: 
- The Prism in the image is dead
- The enemy count says "0"
- The image present in the center was converted from image to Mindustry's "logic pixel displays" using a modification that converts images into these displays.
I may not be able to give much information of games outside of Event Horizon RPG, but it may be certain that the prism has been defeated.
Senery, if you are a bit skeptical about this, I am too.