Difficulty spike is gradual, but gets overwhelmingly annoying by the end of the story. If you want to have fun, just stick to the basics.
This is coming from someone who has been playing with a veteraned player. Even they have troubles with specific parts of the story, and wish to not partake in those either, but wants to do so just to help friends. If that's enough to say, then that's enough to write about.

This game has always been a pleasure to play, and I will keep up the work with play time as I heavily enjoy this game.

All in all, this game is really fun to play online as the Idle game: Time Clickers. The game Time Rifters needs to have a bit more improvement. The way to create levels, as well as have 4 different teammates that you play as AND attempt to achieve a high score each time is really fun. However, I believe that this game really needs a multiplayer function so that you can attempt to play with your friends online. I may just be blind, but all that I saw was a way to record playthroughs to your friends or play by yourself, no live action feed, which saddened me the most. If that function were to be added, as well as separate gold for each character in the game so that some don't level up faster than others, then this game would be really fun. I still recommend this game to others, just not in the way that would be useful to most.