This is odd, as the BeginPlay event causes the player's HUD to appear earlier in the main menu, when it should appear at game start. The solution is to move the HUD logic to the Level Blueprint. The health bar will only be generated and displayed when the level loads and starts, not when the main menu is active. It turns out that levels have their own Blueprints.

The next problem is that the enemy isn't moving. This is odd; it was still moving yesterday. The enemy can only move at the beginning, so it might need to be recreated.