Thanks for playing, I watched your video playthrough and I see the confusion. Most of it comes down to we didn't add enough feedback to the player when things were happening. Whatever angle you come at the enemies from you do a bit of damage to them if your head goes into them..
We had planned to add animations, vfx and sfx to indicate you were damaging the enemy but we didn't manage to get those finished in time before the jam submission period ended. I should've coded a basic health bar to the ants as a basic indicator that you were hurting them even without having the vfx and sfx ready, that was an oversight on my part (the main coder on the team).
Thanks for all the feedback, it was really valuable to see how you played it on the video too as it gives quite a good insight into things we should improve upon in the update we're planning in the weeks following the jam voting period ending.