I had a pretty good time with this and ended up playing for around 40 minutes. I like the idea behind the threads. Deciding when and where to release groups so you can distribute pressure around the stronghold gives the usual wave-defense loop a nice twist.
The main issue I ran into was the difficulty curve, especially by Wave 4. I could regularly get through the first three waves without taking any damage, but then the final wave would overwhelm me almost immediately.
Once there are a lot of threads with short timers, it also stops feeling like I’m making meaningful decisions about when to release enemies and starts feeling more like I just need to click every thread as quickly as possible.
I think giving the player a little more time or making the thread choices more deliberate could really strengthen the best part of the game. I’d rather have fewer threads where I’m genuinely deciding which group to release next than a lot of them that all need attention almost simultaneously.
The tower buying/upgrading worked well, the controls felt responsive, and I liked the idea of managing enemy distribution instead of only building defenses.
Solid foundation. I think some balancing and more room for decision-making would go a long way.