I am writing this article a long time ago my game Quadratus was published on Android Market.
During the 6 months more than 5000 users had downloaded my game - and I am very happy about it.
I got a lot of positive feedback, which is really great, I am glad that people love this game.

Android Market has great statistic system and I can mine a lot of informations from it: e.g. now I know how many people use what type of smart phone, which version of Android an so on...
This will definitely help me when I develop my next game.
This was my very first Android app and there are several errors in it, I know about them and I will try to solve them.

BTW I made this game for some HTC competition but I did not win :(
I was in a hurry because I had no experiences with Android and the competition took only two months - and I got to know about it too late.
Luckily there were some problems (in organization team) and all attenders got another month to polish their apps.
I finished the app on time (one or two weeks before deadline) but suddenly I got the message that my game is not working on Android 1.5! This was minimum: so I had to rebuild it to run on 1.5 - thre were no problems with it and I finished it one one day.

The very first version of game (that one for competition) has only 10 levels and later I decided to add another 40.
My idea was to create about 100 levels, but many of my friends who tested this game again and again got bored in
less then 20 levels so I decided to create only 50 levels.
Some of the levels were so hard that people stucked in level 4 and stop playing so I lowered the difficulty.

Somewhere in January 2011 I got an proposal from one Korean company to modify the game for Korean market: because Google's Android market was not available in their country the Koreans could not download Android app. Also every app in Korean should wear a Rating symbol so they asked me whether I can add this symbol to their game.
Rating symbol: For all
With this symbol, the Koreans can download my game.
I agreed and did that for which I got $200 USD. I was happy, that was my first (and only) money I have for this game!

I have several other ideas for free simple games and maybe one time I will also create some paid application (nowadays I have only license for free app on Market).
Now when I am more skilled in android SDK I suppose that it will be easier for me to develop another apps. Also I started to play with OGRE3D for Android, which is great Open source 3D rendering engine and with it I am able to create simple 3D games, which is really cool :)