Today's update:

• Formulated the minimum set of graphics as text and a set of references - it took quite a lot of time, despite having already picked out resources and having a clear understanding of what and how things should be. Used notion to keep this document.
• Started rethinking the system for the hot air balloon's flight (I'm not very happy with the current logic, as it quickly leads to an artificial end of the game when the balloon takes off and moves in a straight line). This in itself doesn't look very good, so I'm thinking of how to change it to something more natural and physical.