And should I fear trying to do more than one "semicolon-separated thing" on the left side of an if/unless statement?

Yes :-). I'd use do{...} over eval{...} because do doesn't have the nasty habit of eating fatal errors unless I explicitly check for them. I'd still reverse the logic and put the consequent to the right side:

perl -e 'my $type="blee"; if ($type ne "newer" and $type ne "older") {
+ print "bad type\n"; print "blee\n"}'
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