1. The game idea. I usually start with a pretty clear idea of what i want to make, most of the time a clone of a game i liked (16-bit era games mostly)but that lacked features or has clear flaws in it's gameplay
2. Make some graphics for it (because i hate experimenting with primitives, i usually try to get something that reflect more or less what i have in mind
3. starting basic gameplay, usually full character movement and collision stuff
4. making character statistics, adding items, effects, ennemies.
Stuff such as collectibles, medpack, powerup, or spells and some ennemies with a braindead AI
5. start building a level that is close to what i want to get in the end (<- never succeed)
6. start to make some more mechanics, mostly interactions with the environement such as doors, elevators/platforms, teleporters.
7. start a basic GUI system
6. searching and applying sounds for all this
7. ... i never past point 7. To me it's always the same :
- At this point i usually have 15+ dofiles and lots of single variables that cross multiple files, so i get lost.
- blender inefficiency at level design + no objects/materials library system results in a giant mess for making levels
- Game mechanics that works, and then who broke when you add or tweak something,
resulting in fixing the same stuff thousands of times, this is the main reason that makes me abandon a project.