The MM1 and the Mikor MLG work best all the rockets will get you through the game. I don't find any difference between hard and easy settings, I think the game is a bit too easy.
Awesome game, I love the puzzles, couldn't you have just made it the puzzles though?
You have to run both modes together to beat it. eg first attack answer is typewriter, I got that by turning the roman numerals into letters based on the largest # of numerals I could use, it turned out to say tvpewrator, which was easily turned into typewriter.