Creating a complete Android game from scratch in one month

I wanted to build an Android game for some time, but never got some good idea. Lately I have been playing Subway Surfers and got really passionate about it. I usually don't like the "endless" games, that you basically cannot finish, so I always set an arbitrary goal to reach. This time it was reaching 30x score multiplier. While I did that, I got some skill and really got addicted to the game. It also made me realize that Android games don't have to be a AAA title with huge story and complex gameplay. Something simple and casual is OK.

Anyway, I thought it would be nice to have a game where you could simply point your finger at something and shoot it. With a system of Missions, Daily and Weekly Challenges and weapon upgrades it could be fun. My first idea was to create a game where some cute monsters would run around a beautiful scenery, hide behind the trees, old houses, or even in the clouds and you would need to shoot as many as you can. By cute monsters, I mean something like Gremlins. They would also bring in some huge machines and do other stupid things that would make you laugh. Of course, being an indie game developer with zero budget, I decided this would require too much art and too much of my time because of complex animation I envisioned. So I decided to use a different setup, something I can produce myself in a reasonable timeframe.

My goal now is to make an interesting, playable game for Android in one month.