Thanks. I have reconsidered the difficulty level.
The recycling bin enemy appears from stage 3, but by then the player must summon the Wall Window. In the first version of the game, there was not enough mana to summon the Wall at stage 1, and the Space Cadet Window (the weakest Window) has only 2 HP, so the game could be over before the player realizes the importance of the Wall.
Therefore, we adjusted Space Cadet's HP to 3 and the summoning cost of Wall so that it can be summoned even from Stage 1. This will give players more chances to realize the importance of Wall.
Thanks for the feedback!