Pulling this from the other thread...
I enjoy Megaman Battle Network 4. It's kinda just really bad, having a script that was functionally an afterthought (the A plot happens in the background until the last 90% of the game, and most of the B plot is just filler and making you do obnoxious challenges because otherwise it would be two hours long) and was translated so poorly that you can feel the untranslated Japanese breaking through the text, has the absolute worst new game plus system, the new Doublesoul system was unbalanced, the game flat-out locks you out of the postgame if you don't play how it wants you to, so on and so on and so on.
Interestingly, I love it because playing the way the game doesn't want you to is fun. Dark chips provide a massive amount of immediate power, but come at the cost of fucking with you for the rest of the battle and permanently reducing your max HP by one. It's supposed to be to a maximum of 501 below your pre-darkchip max, but the game is bugged and functionally goes to like -800 if you do a normal run to NG+2. It's high risk, high reward. Which is really fun compared to the low risk, obscenely high reward of playing light. The final boss also "purifies" you, but he does it in a way that made it obvious this was never supposed to be something you should do to begin with. You're still treated as evil by the mood screen, and so can't enter the double damage Full Synchro or Anger status, nor Doublesouls. You can't use normal or SP versions of chips, which you can't use while dark. You aren't experiencing a newfound redemption; you're being made to play with the drawbacks of being evil but none of the benefits. Lastly, you enter the new game still as evil as you were before.
The issue is that in order to enter the postgame, you need to give the base version battlechip of every boss. This isn't something you can do for Shademan, one of the only three villains in the game, because he doesn't have a fixed encounter that drops it guaranteed. And a side effect of being dark is that you always get the DS chip (only version usable by dark Megaman) outside of the fixed encounter. You can't leave the deep darkness (which you are inevitably in, if playing dark) unless you get something incredibly deep into the postgame, which requires you get something you need to be out of the darkness to get. Thankfully, you can trade with other players.
It has a great soundtrack, too. (There's supposed to the the tournament battle theme here, but I can't edit the message to grab the link from my post).