If it wasn't official, why does this specific keyword exist? There are three likely explanations for the "171" tag:
Castle Crashers is a 2D beat 'em up video game developed by The Behemoth. It was first announced at Comic-Con 2006 and became a defining title for the Xbox Live Arcade (XBLA) service during the seventh generation of consoles. Known for its hand-drawn art style, humor, and cooperative gameplay, it became an indie sensation. castle crashers psp iso 171
Since there is no official PSP version, your best bet for a smooth experience is playing the official Remastered version on current platforms. If it wasn't official, why does this specific keyword exist