This may mean playing the game on.ly for a few minutes. Praise, but don't criticize. Make the play challenging but not frustrating for your child. Play and learning go together, especially for your toddler. Keep play light, creative, and fun.
Sharing is a very difficult thing to learn.
We don't expect children to be able to share until they are at least 3 years old, but you can begin to lay the foundation now. Children probably learn best by having many good sharing experiences over a long period of time. Set a good example. It also helps to demonstrate sharing behavior. For example, you've just cut an apple in half.