I thought the last level was a little bit hard though, and then realised that we could upgrade our army with the barracks... I almost made it to the end without barracks tho! I had very close tries. Did you manage to do the last level without upgrades?
The last level is almost impossible without the barracks. The boss and the waves come too fast for you to keep up with (I was only able to beat the first 3 without upgrades). Maybe with very lucky enemy spawn RNG, it might be possible. The reception of the game’s difficulty seems to vary widely among people, so in the future I could add a difficulty toggle (easy, hard, extreme, etc).