finished with 26 lives left. Just finish it with 25 left, then play the level with the vehicle thing again, jump around a lot at the front of it, and after about 5 tries you'll get thru it without having to make a sacrifice.
last boss ruins this game... at least shouldn't have to replay the entire level, or the last level shouldn't be half as long. I tried 4 times and I'm not even sure why I'm dying. done now.