I regret playing King of Fighters Neowave (feel free to skip it, it's meh, there are way many better KOF games, although this one is definitely better than 2001 and 2003, but still, it's not great in my opinion and i don't like it much for some reason) and Mortal Kombat 4, meh game in my opinion. (though Gold is decent and gets a pass)

I love other KOF and MK games, but these, not so much.