Yes, thank you! The squares are only a temporary effect for some of the enemies which don't have a death animation yet, it's as old as 2011.

Previously there was no player death animation, instead the gameplay froze (as it does now) and oftentimes you could see inaccuracies with the collision detection so I decided to make the character model invisible on death.
Generally I like the concept of an explosion into multiple spheres as it's inspired by Megaman (and Super Mario Sunshine) and as a result reminds me and hopefully other players of those games. I will try different or advanced approaches, though, and I'm open for suggestions.