Upgrading your prosthetic tools and boss rushing basically. Also challenge runs. Unfortunately this game doesn't have the replayability of the previous games. But still it's a really cool game.
While I agree with your first part of upgrading prosthetic tools and boss rushing, I disagree that this game doesn't have the replayability of the previous games. I actually completed Sekiro 5 times now, all the way to NG+3 and also another completed fresh NG because I want to see all the endings + I want to see how it feels like to fight against Emma + Isshin in a fresh NG and NG+, the difference there not having as much upgrades and having all the upgrades when fighting either of them. I still have another NG+, the continuation from that very fresh NG, in progress but because of Expedition release for Underrail I'm not playing Sekiro for now.
I don't know, maybe I don't really care about playing different builds in an
Action-RPG, maybe I don't really care of experiencing new content in NG+ cycles like in Dark Souls 2, maybe I don't care much for PVP and co-op, but the overall gameplay of Sekiro, heck even its combat gameplay alone, managed to carry it for me, enough to replay it several times more than I'd normally would. In comparison, the rest of the Soulsborne games, with the exception of Demon's Souls since I haven't the opportunity to actually play it, I only replayed them all like.... twice.[/QUOTE]
I'm on playthrough 10 now on Sekiro. The combat system is addicting, period. The level of polish, the music, the mobility, the counters, especially the Mikiri (seriously how awesome is it that you side step the attack and then place your foot on the blade pushing it down?), the sound of the blades clashing, the bosses, I could go on. The level of quality of this game is through the roof, off the charts, no question about it. I think I might like even more than DkS 2, even though it's lacking many things. However it just goes to show that even if a game that doesn't have the vast amount of content DkS 2 has if it's done well it can surpass others eventually.
There are some seriously talented people at From Software.
But unfortunately it has almost 0 replay value. I mean, the love for the combat system can only carry you so far.
There is however a boss rush mode that contains some QoL upgrades besides boss replay so there's that. Watched LobosJr. play through it and it was awesome. Going to try it later.
Edit: well, looks like my quoting skills aren't exactly on point. Still learning how to quote properly, but damn.