To play this ISO on a modified Xbox 360, you typically need to convert it into a format the console can read from a hard drive:
Check out these guides for ripping, extracting, and playing Xbox 360 ISO files on modded consoles: How To Rip And Convert Xbox 360 Games To ISO/GoD/XEX YouTube · Aphelion Gaming How to Play ISO Copies of Games (RGH/JTAG) YouTube · Matt Darnell
Use tools like Xbox 360 ISO Extractor or WX360 to unpack the files. BulletStorm [Region Free][ISO]
Xbox 360 (can be played on original retail consoles if burned to a disc or on modified RGH/JTAG consoles via extraction) Usage for Modded Consoles (RGH/JTAG)
Alternatively, use ISO2GOD to convert the ISO into a GoD container, which allows the game to appear directly in the official Xbox dashboard. To play this ISO on a modified Xbox
Region Free (Compatible with NTSC-U, NTSC-J, and PAL consoles)
Move the resulting folder to your console's internal or external hard drive via USB or FTP. Game Name: Bulletstorm Format: ISO (Disc Image)
Game Name: Bulletstorm Format: ISO (Disc Image)