The best of the Mega Man series!
This game features Mega Man with his arm cannon. Throughout the levels you can find energy tanks to save for when you're extremely low on health. The game features a password system for each boss that you defeat. For every boss you defeat, you also arm yourself with their weapon. This weapon will be another bosses's weakspot, so finding out who that is is part of the fun of the game.
While this game did not feature Rush or charging your Mega Buster yet, it offered the best overall gameplay and bosses. Every level in the game is fun to play. Well ALMOST every level. Heatman's level with the disappearing and reappearing blocks was a headache but after playing through that level 100's of times over the years, I think the pattern has been engrained in my memory.
I can't think of any reason not to recommend this game to anyone. It's now part of a Mega Man collection for GC, Xbox, and PS2 and is well worth picking up as well. This is still my favorite Mega Man to date and I strongly recommend it to anyone.