An interesting idea, but the balance was completely off. The game was no challenge at first. I could just stack all my units at the front and the hero could maybe kill a couple before dying. Then the hero got the life steal perk on the 14th run and they became literally unkillable. Even against a massive hoard, once their armor broke their health never left full, where in the level just before they would die after about 5 seconds.
Also, for some reason the game kept trying to load SteamVR and the audio would automatically play through my vr headset.
Good concept, though.