Just terrible
Sure, it looks like a complete game. But there is so much that is missing.
As many others have said, the ads are terrible. If you want to make money from your games, sell them to a site like ArmorGames. A few ads are OK, but this is just too much.
Additionally, the game simply isn't tested. I tried shooting the canon at an angle of about 80-90 degrees and the shot never came back down. The camera scrolled about 20% of the way to the enemies then stopped.
On the topic of scrolling, there's no way to scroll around and look at the enemies after you've clicked to see your catapult. Every other half-decent game of this type lets you scroll back to get another look.
And how about weapon selection? It's not intuitively obvious what's going on without experimenting to figure it out. To the average gamer, 4 single arrows and 1 triple arrow means they have 5 shots, not 2 or 4. While I'm talking about arrows, there's no way to see whether you have the single or double arrow selected. I didn't make it far enough to see if any other ammunition types have the same problem, but I imagine the same problem occurs later on.
TL;DR: Let some friends play your game before you release it. This seems like a game that was only tested by the dev - and that's a problem. It's hard for devs to spot problems in their own games.