Interesting merging mechanic that becomes clear after a bit of experimentation. I liked combining the circles, but missing music/ SFX drops experience here! Still, good entry. This is what I thought in more detail:
Game play / Fun / Engagement ●●●○○
The core idea is clever and has potential, but it feels somewhat 'underdeveloped'. The lack of variety and feedback during merges makes the game less engaging over longer play sessions.. But I like that you need to pay attention when to actually drop a ball. Thus, much potential, but also needs polish. 3/5
Art Style / Visuals ●●○○○
The visuals are functional but very minimal, while it feels like a prototype. You used the given shapes only, so this is a bonus! But there’s not much polish or flair. Adding some small effects, like particles or a light shake when circles merge, an interesting UI etc. would make the game feel more alive and satisfying. 2/5
Audio / Sound Design ●○○○○
This is where the game is lacking the most.... Without background music or sound effects, the experience feels a bit empty. Even simple sounds for merges or a subtle loop in the background would go a long way to improve experience. 1/5
Theme ●●●●●
You nailed the theme of course. The limited space works perfectly with the game play concept. The mechanic of being limited with the dropping of balls feels like a natural extension of the theme! 5/5