My Top Down Game in Unity

I am currently making a top down 2D game in Unity. My game is about a square that needs to get to the castle that will be the final level, to rescue his shaped friends. The game will start easy but as the player progresses through the levels it will become harder for the player to get to the last level. During each level the square will need to dodge bullets fires by defences places around the levels. Each level will also have its unique design. For example the first map is set in a village, the next map could be set in the mountains or in another different environment. Also in each level there will be boosts places to help the player get past the defences faster and get past the level.