First off, well done! This is great, especially for your first game!
I had fun playing. I like that you don't have full control over the battles.
It's a bit slow in the beginning, as others have mentioned. Maybe have the early upgrades and buildings cheaper? In the end I felt I lacked the resources to progress. I had chopped down every tree, killed every sheep and picked all the pumpkins and mushrooms. They just didn't respawn fast enough so I idled a lot.
Another thing I noticed was that the goblin buildings respawned, but they still had the "clear the rubble for 1200" message when trying to attack them again.
Hope you had fun making it. Would love to play it again if you choose to continue working on it.