You're able to make almost ANYTHING. RPGs, 3D mazes, actions, puzzles, Smash Bros (more basic version of it of course)... you name it. However it does require constant learning. Beginners should start with text-based games or just simpler things like moving a character around, and then build on your knowledge base.
Or, you can just download and play people's games. Playing is learning too!
1そうだね 未プレイ