I think mechanically, there aren't really any flaws I would point to. Everything works without bugs. Design-wise, I would change a few things. I didn't really get the impression that the player was the enemy beyond the story, since the guardians looked noble and the enemies looked evil. Even a small looping animation where the crystal is chained up and trying to break free would work. Speaking of the crystal, the control ability didn't feel particularly impactful. I know there was a stat boost attached to it, but its difficult to notice that, and since the towers controlled themselves fine, I didn't end up using it. Maybe replacing it with some kind of magic artillery from the crystal would make for a more impactful cooldown-based ability. Also, the option to change targeting of enemies, I think, works best when there's some kind of limitation on how fast towers can rotate to target enemies. In this case, it was instant, so it didn't feel like I ever needed to use this option. I did like the egg system, I'm a bit of a sucker for loot crates. I think that also naturally incentivizes more playtime. Overall, nice work!