Forced logging to stdout with no way to turn it off. No support for connect_cached or any of the hash fetching functions (eg fetchrow_hashref).
Interface is basic - the docs more or less encourage you to explicitly set the sql you're waiting for and return a fixed value when it is run. It *is* possible to do regexp matching on sql and return the result of a coderef, but it doesn't pass the sql to the code, so its use is limited.
The code is readable, but indenting is off, and it "use"s Data::Dumper twice :-)