PAC-MAN MUSEUM+

Go to options, change difficulty to easy and lives to 5, this will help with the high scores. You have unlimited continues as well. There are 6 worlds with 5 levels each so just play through to the end of the game and after beating the final boss you should hopefully have completed all of the missions but one.

You will be at 30/50 stages complete so just start the game again from the beginning and complete the first 4 worlds for the final 20.

Not too difficult overall, the ghosts move much slower than you, and there are tons of power pellets in each level, so just keep playing and you will have it all done in under 2 hours.