A broken and boring game, really.
But I played it just to see how you can improve.
You know how to implement a shop system, and you have a variety of paint schemes. It does add a nice touch to the game. The shop also says you can click on the item again to unequip that item. However, doing this just repurchases the item again and wastes money.
The art is rather basic, but I rarely judge games poorly based on artwork alone. Besides that, the art is appropriate enough.
I was kinda hoping for lightning streaks across the plane for the Lightning paint scheme. I get the cartoony lightning bolts instead. Oh well.
The game itself is very plain. In fact, it's merely a game where you tap the spacebar in short bursts-repeatedly, so that the plane stays between the clouds and the trees. There is no story, no goal to reach, no enemies to evade or defeat, no other levels. Just... flying endlessly with the looping background until you get tired of it.
I played long enough just to see where the multipliers in the upgrade menu stop. Apparently, I've been able to get upwards to 90x multiplier, which means that you get thousands of cash and points quite quickly. The Multiplier cost always stays at 1000 cash to buy, but since you get thousands, you can pour more into it. This in turn makes the cash and points add up quicker. Thus points really mean nothing. Do you see the problem without putting any multiplier caps and incremental costs to the multiplier here?
As you're just starting out, then I suppose the quality is acceptable. But I've got to be honest with the score. Just don't give up though, and keep making more games while you enjoy it.