What was the score of the game on April 28 where Buffalo were the visiting team?
CREATE TABLE "playoffs" (
  "date" text,
  "visitor" text,
  "score" text,
  "home" text,
  "decision" text,
  "attendance" real,
  "series" text
);
SELECT "score" FROM "playoffs" WHERE "visitor"='buffalo' AND "date"='april 28';