Managed to get till wave 10 after a few tries lol.
I like the idea a lot. I also think the game that you've built around the idea is cool, though it could definitely use some balancing and additions.
I love the presentation though. Everything from enemies, to your skeletons, to even the player itself was pretty readable and intuitive, even when things were getting very chaotic. Also loved the various enemy types ( though I'm not sure what how the 2-headed enemies were different from normal ones ). That said though, I'm not really a fan of the audio.
In general, the audio felt a little annoying at times ( imo ). The music was fine, but a decent amount of the sound effects started to get a little painful to hear.
As for the gameplay, while I do like the overall loop, I think the base stats of the player could use some adjusting. I get that you kept the player slow so that the player can't just outrun enemies, but also so that they NEED to take cover around their minions so to speak. It's a cool trade-off to really make you feel like a glass cannon, which is effectively what a necromancer is supposed to feel like. That said, I think the player's base movement speed could be a little faster. Mostly because the pace of the game and the aggression of the enemies really requires it.
Along with adjusting the base stats. I think the player could also use another ability at the very least. It got a little monotonous waiting for the minion spawn spell to recharge. Maybe a teleportation spell to help with movement or something could help in this regard. It could also work on a cooldown and maybe allow you to teleport wherever you click at or something. I say this because some of the main reasons I kept dying sometimes was because there weren't any more enemies around to resurrect and I couldn't get to other corpses fast enough. This might be a skill issue, but I thought it was worth noting.
I think the variety of enemy types that are currently present is solid. I love how the enemies with the aoe attack force me to move around since I tended to stay in place in some waves . Though I feel like the amount of damage that they all do is a bit too much. It feels like you get insta-killed by almost every enemy if they get close enough. I think the damage they dish out could be a little more forgiving for the sake of balance.
On a side note, towards the end of this run I got the upgrade which resurrects all the zombies around you. Combined with the fact that I was spawning 5 skeletons for every corpse, and it felt godly lol. The game also started lagging pretty hard because of how chaotic things became.
All in all, this is a very solid game built around a cool concept. Good stuff