Recently, I was playing a game on my 2 year old lg g4 carrier verizon 32 gb, egg Inc, and the phone showed a weird arrangement of colors on the bottom half of the screen and went unresponsive. Then when I tried turning the device back on it wouldn't work (no response). So I took the battery out and put in my other one and it turned on, only to show a black screen with small white and red text on the top left, like a console output of some sort. I couldn't tell what it was saying because it was too small. Now it turns on if I take the battery out and put it back in but only for like 30 seconds, and is acting strange. I can never actually use it. It is probably useful to note that it had .21 gb of storage left, and I did not update it to the VERY newest version because I didn't have enough storage, last time I updated it was sometime this year (I have a recent version) but not the VERY newest. NO it is not rooted. It never goes past the LG G4 Screen.

What is the problem and how can I fix it?