The Nintendo Switch received a flawless port of Castle Crashers (the Remastered version). It runs at 1080p docked, 720p handheld, includes all DLC (Pink Knight, Blacksmith, etc.), and features 60fps gameplay. If you want the authentic experience on a device that fits in your pocket, buy a Switch Lite and download Castle Crashers Remastered from the eShop.
The PSP Go (2009) attempted to go digital-only, but the majority of PSP users relied on UMD discs. Castle Crashers relied heavily on patch updates. The famous "Insane Mode" glitch fix and the Necromancer Pack DLC would have been a logistical nightmare to distribute via UMD. castle crashers psp