The Hero Gate is located to the north-east of your starting position. Once you have a small force of trained creatures (around 3-4 creatures at level 2+), begin digging a path towards it. Be cautious as you approach, as there might be a few weak heroes guarding the gate. Use your 'Slap' spell (LMB on creature, then RMB on target) to direct your creatures in combat. Once you reach the Hero Gate, simply have your creatures attack it until it's destroyed. This will stop the flow of new heroes into the level. After the gate is gone, systematically hunt down and eliminate any remaining heroes to complete the mission.
