Hints

I remember struggling so much in the Stronghold stage. The trick is pretty simple though; Lava and Iron Bars. There are only 3 places to place turrets. Placing a Slime Dispenser there helps a ton as the Slimeballs slow down enemies drastically. The only upside to this trick is Creepers which come from the top. My strategy at first was using Trapdoors to get rid of them but I struggled at making enough Gold. So I scrapped the Trapdoor idea and instead used a lot of Lava to get rid of them. If the Creepers touch the Iron Bars, they will explode. When they explode, everything with a 2 block radius will go too. Honestly the creepers will be the only problem here. But they should die with enough Lava.

Then there was the dreaded End stage. I used to always get to the end of the stage and lose because the Dragon would blow up the wrong things. For the first two, I just placed Egg Dispensers with high Damage and Rapid Shooting. In order to clear the stage, you need to blow up the End Crystals (which is why it doesn't exist in Survival). You need to place TNT on the End Crystals. When you blow up the End Crystals in Phase 1 and Phase 2, you can quickly delete all your Turrets (which for me was just one super strong Egg Dispenser) and get the Gold you used to place them. Don't plan on farming gold forever as the Dragon will come and blow your turrets up. I recommend not using Speed in this stage as your reflexes need to be very good if the Dragon tries to blow up your Egg Dispenser which you can quickly delete and replace. At Phase 3, you need to blow up the Dragon Egg with the Dragon's attacks. My strategy was to place Cacti right next to the Dragon Egg. The Dragon will fly above in every round, shooting at the Cacti. Again, using Egg Dispensers are optimal. And after somewhere around 2 minutes, the whole stage should be finished.