this is a great example of a simple game that's been very well polished. Great effort. To echo Vimlark, yes it can be a bit repetitive, but that is due to it's simplicity. What you have here is a very solid foundation to build a great game. Your next step should be to add in some variety. Perhaps consider power up drops like shields for the player, speed boosts, de-buffs that slow you down, horizontal attacks (as you have a jump ability) and I'd definitely add stages, for example survive for 10 seconds and reach stage two... at 25 seconds stage 3 etc. Lots of potential here.