Slowing down and texture problem

[Tilika]

Hi, I was playing on my PPSSPP emulator when suddenly, I began to have some laggy and texture problems. It was working completely well in the beginning of the game so it's not a performance problem ... I really don't know what happened. Here are some screenshots to explain the problem :

   
The first one is showing the texture problem ... As you can see, the color of the floor is supposed to be the same as the color of the stairs but I became grey.

   
The second one is showing another "weird feature" of my bug, as you can see, there's no map, just a projection of my character where the map is supposed to be.

These are really annoying problems for the gameplay, and the worst part is that I don't even know why these problems appeared ... I tried uninstalling an re installing but it didn't work .. :/

Thanks in advance for your answers

Edit : Well now, my character turned to green ... And I'm like at 10 fps