Hi Einswine! I'm so glad you liked the game.
Regarding the inventory slots, it is limited. The slots for 🌼 and 🪨 you can get in the game are limited to what's needed to complete the goals; i.e. to befriend the townsfolk and to fully upgrade all your tools.
The defeat 5 💀 goal is indeed the most difficult to achieve, and it is the very reason why I added the "Relaxed Mode" (see Different Ways to Play) so that even if you don't complete it you can still score.
I appreciate the feedback and I'm always open to it as I continue developing the v1.4 which I call "Expanded Edition".