Ice Climber (USA, Europe) ROM

Ice Climber is one of those 1985 NES games that is challenging mainly because of the unique way that the characters are controlled. It is a vertical scrolling platform game, where your character uses a hammer to beat up cute enemies and break overhead ice. Immediately above each normal stage is a timed bonus stage full of cute fruits. Its best selling point is the fun 2-player simultaneous mode.
Ice Climbers jump in a very strange way, and much of the gameplay will involve trying to get used to this. This will cause many players to give up in frustration, but many others will stick with it.