Intellivision

Many years ago I liked playing video games. Mattel Intellivision was an early favorite, we played that game until it fell apart. Actually my cat chewed the cords. The thing about Intellivision was the fun factor. Very limited graphically at today's standards, but the game play in baseball and football was very addicting. Some games look good, but don't play well. I want my game to reflect my art style and have simple play that doesn't get boring. I realize that the game may only be played 4 or 5 times after purchase. It is my goal to systematically inflict as much humor as possible in those 5 visits. I am creating for an iPhone. The next issue is screen size in relation to thumbs plus character interaction. How big can I make the characters? What actions are possible?