A fun and addictive high-score game with a clever theme execution and well-thought-out mechanics! Itβs a strong entry overall, though the visuals can feel a bit overloaded at times, and the audio could use more variety to keep things fresh. Here is what I thought in more detail:
Game play / Fun / Engagement βββββ
The game play is very engaging and executed really well. Merging planets is satisfying and addictive, making you want to push for a higher score. The only issue I found is that holding down the left mouse button drops too many planets too quickly, which can be frustrating... Needed to get used to the mechanic. Also: The "next Piece" does not work all the times? But maybe this is due to the quick dropping of planets... It forces players to carefully tap instead, which slightly interrupts the flow. Still, this is a minor issue in an otherwise excellent game play loop! A strong 5/5. This was my high score:

Theme βββββ
Perfect use of the theme "limited space"... and in space! The title itself is funny, and the design makes the limitation feel central to the game play... you literally have limited space for the spheres. Easy 5/5.
Art Style / Visuals βββββ
You used the given shapes well and the planets fit the concept nicely. However, the visuals feel somewhat overloaded. The combination of glows, outlines, and a busy background can make the screen overwhelming at times. Iβd suggest either leaning into distinctive textures for the planets (cartoony styles could work well) or simplifying to clean colored spheres without as many effects. That polish would take the visuals to the next level. Thus, 4/5.
Audio / Sound Design βββββ
The music fits the space theme well, but the sound effects are quite basic and repetitive. Adding different merge sounds depending on planet size would add a lot of depth, and menu/UI sounds would help polish the experience further. 3/5 here.