This is why you shouldn't use spaces and odd characters in linux filenames! Your command to remove the first file should probably be:
rm User-\ Linch\\'s\ No\ rocket\ or\ shotgun\ mod.pk3
that assumes there is no space between User and the hyphen that follows it. You basically need a backslash before any blank space or char like an apostrophy.
I'll leave it up to you to try that, and then if it works, modify it so that it will also kill the 2nd file.