[the_pwner224]

Not flash games, but these are ones that I have done in the past that were good for learning:

For puzzle games, Set is a good one that will let you practice the UI aspect and recording state, as well as scoring. The PDFs here have the rules, https://www.setgame.com/set/puzzle_rules, and you can play the game at https://www.setgame.com/set/puzzle.

For real-time games, Pong is a great first project and can be followed up by a top-down 2D game (probably a shooter is the most common one). For these you'll need to use Canvas.

Unless you're doing something unusual, the game mechanics are usually not the hard part. A lot more work has to go into polishing it and making a finished product.

I would suggest staying away from Unity in the beginning, it adds a lot of complexity and you'll be able to get started much faster with a bare canvas (which you can easily learn to draw on, and create a game loop with setTimeout or requestAnimationFrame) or React project.