Hi developer here, thank you for playing the game! Regarding your confusion on the theme and the limitation: it is not required to follow the theme of this jam, psionic, and is purely inspirational according to the rules. And onto the limitation, you are able to use enemies to hit other enemies on collision. This is especially useful in higher waves where there are multiple enemies moving towards the player at the same time. And without much time to react and drag them away individually, hitting enemies with enemies is the only way to survive in these situations and increase your psi bar. Hope you have a great time playing!