Marvel Ultimate Alliance

For this achievement, you will need one of two things: three real people to connect with online, or three controllers with extra Gamertags available locally. You can either play through the game normally in co-op to get this over time, or if you want to quickly get it (especially if you're using four controllers by yourself), you can simply load up Stark Tower in Act 1 and enter Iron Man's secret lab. Return back to Stark Tower and that is considered one level complete. Repeat 24 times.