While many sites offer "free full version" downloads of the NES or SNES versions, these are typically ROM files that require an emulator (like Mesen or RetroArch) to run. 3. Avoiding Malware & Scams
This is the most stable official way to play the original Battletoads and Battletoads Arcade on a modern PC. battletoads-download-pc-game-full-version
The newest entry in the series is natively available for PC with updated 4K hand-drawn graphics and 3-player local co-op. While many sites offer "free full version" downloads