Hi Pepez, nice to meet you! It was cool to play your game, I think it has a lot of potential depending on where you go with it.
Here is my feedback for the game as-is right now. Feel free to take it or leave it -- it's your game so it's up to you to decide what's best for your players.
Level Difficulty. When I first started playing, it took me about four minutes to hit all 5 of the rings. A lot of Flash game companies have the rule of thumb that the player needs to be having fun in under one minute, under 30 seconds if possible, because about 60% of players quit every game before ever getting to level 2. I'd bet if your game was released to tons of people right now and you tracked when they left the page, many people would quit before completing the first level. They might think, "Ok, I understand this game, I got the first one...AUGH I have to get five more?? Boo."
My Suggestion: For the first level, only require them to get one or two rings before completing. Then make them feel awesome for what they've done.
Level Progression. As far as I could tell, every level was the same. Randomly place five rings on the stage. I don't know if that's how it actually works, you may have hand placed them yourself, but the point is that's how it felt to me as a player. Unless there's something new and exciting, I as a player am not really compelled to complete it. I just think to myself, "I finished this already. Done."
My Suggestion: Do something to distinguish the levels so that every time a level loads, the player thinks "Oh! I haven't seen THAT before. Let's get rolling!" The suggestion above for slowly increasing the number of rings from 1 to 2 to 3 would do part of that. Changing the backgrounds would aesthetically be cool. But in terms of bang for your buck, you're probably going to want to introduce new Base Mechanics every few levels. Some quick ideas: Blocks that stop you or are in your way, rings that move instead of stay still, black holes or galactic tides that push and pull you, enemies that shoot you and hurt your time score.
Scoring Guidelines As I said, I beat the first level in about four minutes. I might imagine you read that and thought "Whoa, he's awful!" Am I? I dunno, I thought I was kind of awesome. My point is that I have no point of reference for what's good and what's not. This is a problem in a lot of score based games: someone might beat the first level in 60 seconds, and someone else beats it in 10 minutes, and both of them can think, "Man, I'm awesome at this game. I beat it already, mastered it. I quit."
My Suggestion: Add a point of reference for time. A Leaderboard that shows up BEFORE the level starts, or a "Today's Top Time: 1:34" right below their own time. Or just show an arbitrary number that you pick out, like 2 minutes, and tell them that that's the bonus threshold and they get a bonus if they can hit it.
Some other smaller items:
- I was disappointed when FB Connected and it said I had a high score, but I didn't see it anywhere. Like an arcade cabinet I expected to see a leaderboard pop up. Clicking the High Scores button didn't work.
- I wish that it told me the keyboard keys when the first level was loading. I was using the clunky mouse buttons for a long time because I didn't bother to click the "Instructions" button.
Best of luck!