I picked up Tap Titans the other day. When I started the game, I thought it was one of those basic clickers, with basic progress forward. There are plenty of those, where you get incremental bonuses to reach an end point.
That changed after a bit and learning about Prestige. When you reach a certain point in the game, you can restart the game from the beginning but get to keep certain features, making the next attempt a bit faster. The difficulty curve grows near exponentially, so you end up hitting a wall and wondering what’s the point and it dawns on you that you need to restart.
Cookie Clicker is probably the most notable game like this, where you restart progress to get a bit farther next time, though the interface is rather rudimentary. It’s an offline game really, where progress is made in chunks, rather than in a consistent amount. Kingdom of Loathing has a similar mechanic, where once you beat the sorceress, you can restart fresh keeping most of your items but losing levels. You also get to keep 1 skill from the previous class you beat the game with. This type of game adds a new level of strategy, where your playthrough isn’t so much for beating the game but for preparing you for the next run. And you get competitions going where you see who can beat the game (and restart) the fastest.
While Alternative Advancement (EQ, Rift come to mind) and Paragon Levels (D3) provide a very long tail end to the end game. Where some can hit a gear treadmill, these alternative paths let you continue to move even if you have all the other carrots in game. I’m thinking a bit of WoW right now, in that outside of heroic/mythic raiding, I had completed nearly every possible thing to do in WoD. All the treasures, all the bosses, all the garrison buildings. In under 2 months. The only thing in WoW that crosses characters are heirlooms, and they are used solely to bypass existing content. FF14 has found a neat way around this, in that any character can be all classes. You restart at level 1 but maintain the progress you had from the other classes. So each character has a ton of carrots.
The more I go about it, the more I’m inclined to think that the traditional progress (just numbers) is a dead end. A real long tail to a game is different that seeing a single boss drop down, but in individual/group progress on the horizontal plane rather than vertical. Of course, this becomes more challenging to balance if the horizontal game is so vast and deep that it becomes more powerful than the vertical gains.