[Mobile][2010s][free to play game]

Okay so my cousin showed me a shooter game you would start on a server screen and can either join or make your own server and you were in first person, there was a map with 2 buildings I think and a moutain all around but on the biggest building you could climb the mountain by continuously jumping i dont know if it was a Easter egg or a glitch I remember that map and a coliseum map maybe