The first game that comes to mind for me is Civilizations 4. I’ve probably spent hundreds of hours playing but after getting used to 5 and 6 I have a really hard time going back. Going back and forth between 5 and 6 I need to rethink some strategies but with 4 I feel like I need to rethink everything. I don’t know if it’s because of the tech tree layout in combination with the civics system, things like unit stacking, or maybe just a bunch of little things but it takes me a while to readjust.
Played from 2020 to around the end of 2022, already did all of the rebalance stuff since Rebecca became design lead. I really cannot go back. I beat it. It’s done. Regardless of the new frames, etc – I’m out of that “cycle” now. I’m mastery rank L2 if I am remembering correctly. No matter how much content they release - they’ll never release enough of it for me to want to return. I conquered Warframe. Legendary 2 rank. Most people don’t even reach MR15 before they crash out. Once I had everything in the game, it was done for me. Permanently.
Man warframe is such an interesting game. I bounced off it twice. When it first released and then again in like '17, but not long ago I fell into it hard for 3 months. So much so it was my #1 played game for my steam recap lol.