F-zero 99 -nsp--update 1.5.5-.rar

: Added new "Boost" and "Spin" effects that you can unlock through specific gameplay challenges.

In conclusion, "F-ZERO 99 -NSP--Update 1.5.5-.rar" seems to be a legitimate update file for F-Zero 99 on the Nintendo Switch. However, you must exercise caution when dealing with compressed archive files from unknown sources to ensure your device's safety and security. F-ZERO 99 -NSP--Update 1.5.5-.rar

"Until next time, Captain."