Here is a hack for Rush'N Attack which changes the level layouts and adds some difficulty with harder enemies placed in the levels.
Rush'n Attack (USA).nes - NOINTRO
CRC32: ED2C6A3B
MD5: 332C8C5202D4195A567D831F1197C563
SHA-1: 0AD3979BA3C7696166FB60B0461F4409DA653303
SHA-256: CC5EC973848EB372E08EE1F832AA76C8AF6215EDD14100866EA202F06006D2DE