For whatever reason the slow pace of early game kinda stressed me out. There's a button to speed up levels. That will help a lot. My one complaint is more about the level by level we unlock our toys. Feels like another game, that had better level design, no offense. Unlocking the toys one by one doesn't feel great. I understand from a design perspective but from player experience it was more annoying than rewarding. I'd like the ability to unlock everything right away. Play levels in whatever order I choose. Gameplay suggestions, environment effects. Explain the stun mechanic better. Having plots that become affected by damage, weather, enemies. Enemy's could build a tower that spawns reinforcements, weather could leave puddles or mud and zombies could slow down or have different animations based on the weather. Enemies could make use of the weather for special enemies. New toys could affect the field and debuff zombies like support towers. Apologies as I'm still in the early game and have not experienced 50% of what's to offer. These were just suggestions I had while I was playing.