It may sound counter-intuitive, but in my experience, adding constraints to activities can make them not only more fun – but can help generate very creative solutions to problems.
When we talk about gamification and especially when we speak about motivations, we often talk about Agency and Autonomy (the A in RAMP). This would lead you to believe that for certain groups to engage, you need to give them total freedom to do whatever they want.
However, it can often be more interesting to allow freedom within a strict set of constraints. You only have £1000 to complete this task, you have 10 minutes, you have 3 lives etc.