Why would a replaceable battery require a thicker phone?

Simpsons: Hit & Run. It’s nostalgic and offers a surprising level of challenge. I usually do not finish it all the way though, because the missions get repetitive pretty quickly. The writing is pretty fun.

Recently, a guy on YouTube remade the game in Unreal Engine. It’s really fun to watch, but I am a bit sad that will never be able to try it myself.