Super Mario Galaxy (SMG) isn’t a casual game, but it uses a lot of casual game strategies to make it addictive. While the basic mechanics are more involved than your average casual game, they’re surrounding by a host of tricks that casual games use to keep people coming back: level selection, variety, a mixture of short- and long-term goals, high scores, and visceral rewards.

1. Level selection – Nothing kills a gaming session like getting stuck. It’s impossible to keep your levels interesting without making it difficult for some people. One of the best ways to rescue people from frustration is to give them a choice. Instead of being linear, SMG has multiple galaxies you can visit, with multiple stars in each. If you can’t get one star, you can always try a different one.
2. Variety – Eventually, people get bored with any basic game mechanic. To keep things fresh, SMG occasionally opens up a one-off galaxy that has a slightly different way of playing. For example, there are a couple of places where you control a rolling ball instead of just Mario. The occasional change-up keeps the rest of the game enjoyable.
3. Short- and long-term goals – Whenever someone finishes a goal, there’s a good chance that they’ll stop playing. To keep them coming back, SMG gives them long-term goals as well. In addition to the short-term goal of completing a level, players can unlock new areas, abilities, and story by collecting stars and star bits. These long-term goals make the short-term goals more interesting.
4. High scores – People like challenges, but they like them achievable. Personal high scores are a great way to make that happen, since most people are able to improve even if they never get as good as the best. Beating a high score, personal or universal, is another long-term goal to keep short-term goals interesting. SMG tracks the number of coins collected in each level as well as allowing players to share their total scores with their friends. This allows people to egg each other on.
5. Visceral rewards – The best games make you feel like you’re doing something cool. In a way, this is just a very short-term goal. SMG is full of little things that are exciting or visually appealing. For example, at one point SMG has you shoot out of a volcano shortly before it explodes. That’s just plain cool and makes you want to keep playing.