Looking to improve the replayability of your game? Perhaps a level editor is the way to go. Level editors allow players to create their own levels or maps for your game.
Level editors are great when you are trying to increase the amount of replayability that your game has for two reasons. First, they let players create their own levels. Players could spend half an hour crafting their own levels filled with enemies, traps, and whatever else your game might contain. This makes the player feel more invested in your game, and thus more likely to come back to play it.
The second aspect of a level editor is the social side of it. By allowing players to share their levels, you’ve just opened up a whole new stream of replayability. Even players who don’t want to spend the time to create levels will benefit from the system. They will have new levels to keep them occupied while you sit back and watch your game grow (or work on a sequel). You could even add a rating system to the levels, making players compete to create the best levels in the game. Who knows, you might even find some free level designers for your next game.