Day 6: Your prototype, a Minimum Viable Game
Once you have chosen the engine for the development of your game, and before focusing on creating all the mechanics that make your game, it's best to develop a Minimum Viable Product, or in this case, a Minimum Viable Game. This should contain the most essential mechanics for your project, so its scope will be tight enough to see it complete even in less than a month. Attached you can find a video prepared by Extra Credits (one of the best channels I found when developing my game, its content is educational and entertaining), who perfectly explain the idea of MVG.
In Redd's Runaway, the initial prototype took about a week, which consisted of moving back and forth, jumping, and creating random platforms in such a way that the player would find a challenge in moving between 3 levels, discarding cases such as placing platforms that were inaccessible. After that, ask for feedback and iterate over the prototype.
During the development of Gravity Spark, I decided to take several of the concepts from Extra Credits, and before I even made a sprite, I used blocks and other geometric figures to establish the logic of the game. This made the development process more focused, leaving the logic and mechanics at the beginning and then dedicating myself to making sprites with complete freedom, without the pressure of not having finished the game. Once they are complete, adjustments will always be necessary, but dedicating exclusive time to art and other to logic can give you a complete focus on the current task.