I'm new around and also a spanish Computer Engineering student. I've developed my first game in android and though it could be a good idea writing in this forums to tell the world it, so here it goes!
The game is Circle Madness. It consists on 30 seconds games where you have to touch as many circles as you can to obtain the higher score possible. There are squares which you mustn't touch because they subtract points and there are also triangles which appear less often but gives more points. Also, there are circles which give a bonus, like doubling score points for each circle for a few seconds and other bonus.
With the score you obtain playing games you can upgrade things like the bonus durations and other stuff. (There are not micropayments).
Here are a few pics from the game and the url if someone is interested :p
The link: https://play.google.com/store/apps/details?id=com.archison.circlemadness&feature=search_result#?t=W251bGwsMSwyLDEsImNvbS5hcmNoaXNvbi5jaXJjbGVtYWRuZXNzIl0.
Thanks a lot and have a nice day!