Good demo, polished art and entertaining concept.

The only issue I found was the AI of the knights, while it's pretty good, it's not perfect and sometimes they'd go into a whole fight away from the tower (sometimes even off screen) and there's imminent danger at the tower and I lost a few rounds with a whole army of like 20 knights because they didn't defend and instead they were fighting a mob far away.

Other than that, I hope the full game has more units to allow for more strategy, maybe some traps, like spikes or something like that, or maybe mud to slow them down, or maybe walls? I don't know... something. Otherwise I gotta say it got repetitive just as the demo ended. If the game is "more of the same" it will be a bit boring after 20 minutes of gameplay, it needs more tools, and not just upgrades, but new elements to enrich the gameplay.

Hope it helps!