A good initial implementation, and consequently a good game idea — I liked that you added a tutorial, which many games lack, but:
- In the future, you'll need to improve the visuals. At the very least, you could give the slimes 2–3 frames of animation. You could also work on the HUD so it stands out more from the game's background
- I reached a maximum of 30 coins — whether due to high difficulty or because I finished a run, went back to the menu, and started over. At first, I thought 10 coins was the goal, and then I saw 30 in the top right corner. As a result, it was quite hard
- I don't know what further upgrades might be, but if there are already upgrades that affect the clicking process, that would greatly diversify the gameplay