Good encounter, someone brought it up in Unitale and CreateYourFrisk's Discord server and it gave me some bang for my buck.
Might wanna post your encounter in Unitale and CYF's subreddit and Discord server once it'll be done, I discovered I suck a lot when it comes to green soul waves, even more so when the shield's controls are delayed.
Viewing post in Undyne the Undying fight remake comments
Hi, and thanks! I'm glad you enjoyed the battle.
Also, I already made a post about this mod in the subreddit, although I think I'll do another one when the v2.0 will finally be finished.
And don't worry, it's not that you're bad at the green soul waves, those waves are actually a bit hard, but I can't really bring myself on making them easier as it's Undyne the Undying we're talking about here XD. Although maybe I'll do a normal Undyne battle after the v2.0 (still not sure about that though, mostly because I would need to remake a lot of sprites, which is a thing I'm not really good at).