apparently they have a third party who lists each and every democrat as their candidate, offering a second opportunity to vote democrat. republicans ought to do that as well.
Not sure about elsewhere, but that's very common here in NY. Democratic candidates are usually (though not always) also listed under the Working Families Party line, while Republican candidates are usually (though not always) also listed on the Conservative Party line. Votes for a given candidate are counted for that candidate, regardless of which line the voter voted on.