Okay it's a good concept... and can be fun. But that's really all the positives.
I found it really confusing you use an "off side rule", which is completely different to the real one, which makes it hard get to grips with.
Also, at the start it says stand away from the ball to do low shots but i tried this and it just decides to give the ball to the opposition, you can only do pathetic kicks or header it... this means scoring is luck, and defending is almost impossible because of the "off side rule". I understand the reason for the "off side rule" but because the pitch is so small (that's also quite annoying as it gives you zero reaction time) it really isn't needed.
In conclusion, if you add a button allowing me to choose when to kick, and make the pitch bigger OR (not and) get rid of the "off side rule". It is a FOUR STAR GAME.
If you add about three buttons (z,x,c?) for different types of manual kicks, and rename the "off side rule" (if you keep it) and make the pitch significantly bigger, then it's a FIVE STAR GAME.
I hope you do change it