Android Shoot em up Game

Hi, I am new to freelancer. A colleague and I are designing graphics for a shoot em up game. ( similar to space invaders) The game is simple... one button you hold just makes your character move forward and the character is constantly shooting,while trying to hit the "bad guys". You tilt your mobile device to move your character from left to right. Other features - some character upgrades (weapons,armor) - You can view your character profile and rotate your 3D character. You can also see the list of upgrades you've purchased for your character. - A leader board to compare scores with other players. - A shop where you can buy upgrades with game points and some upgrades that you have to pay for with real money. The game can be made in unity or however you are more comfortable with. The easier the better. We will provide all the graphics this just needs to be programmed. The game is for Android devices. If it is just as simple to do it for android tablets as well as phones,we will provide the graphics for both resolutions. Hope to be working with you soon