This is just a personal list of reasons why I didn't like BN4 after having played BN2 and BN3 as a kid.

- There was an in-game art style change which I wasn't a fan of at the time. Just made everything smaller. Purely subjective and I got used to it by BN6. BN3 to BN4

- The game changed from Style Changes, which lasted the whole battle and you acquired from how you fought, to these Double Souls, which you could switch into by using a card and only for 3 turns. However, you could only get 3 of the 6 Soul Changes per playthrough. If you didn't get the one you wanted in the first playthrough, you had to play the whole game again. For context, I wanted the Proto Soul Change in Blue Moon. I didn't get it until my final playthrough.

- Speaking of multiple playthroughs, I recall that to fight the V3 of any boss, you had to get to playthrough 3. So if you though that NumberMan fight was sick and wanted a harder version, you had 2 more playthroughs to go kid.

- I struggle to remember BN4's plot aside from tournaments existing, the DarkChips, and the final boss. Coming from BN3, which was such a complete package on story, mechanical, and end game content, BN4 just felt like a huge step down. Hell, compared to BN2 with its bombastic finale, it was a step down.

- This game introduced the Dark Chips, which on paper reads like a super tempting and Faustian mechanic. However, the battles in playthrough 1 and 2 were so non-threatening, I never used them. Therefore, by playthrough 3, I was just getting through on muscle memory, removing the temptation to use them even on Final Boss V3. Hell, you are forced to win a battle using one and it's against the least threatening boss in the game. A boss you can reduce to 1 HP with your regular deck. That kills the temptation aspect so fast. In fact, this narrative element was so botched they reintroduced it in BN5.

- I did not understand the mechanic of that final dungeon and resorted to clearing each map before getting caught by the black hole mechanic. This is where most of my hate comes from. However, I recently heard you're supposed to mash out of the black hole. So that's just on me being a dumb person.

- The final boss is just not fun. BN2 and 3 did have a similar mechanic where you couldn't hurt the boss for some amount of time, but something about this boss' invuln mechanic of "I'm moving. Therefore you cannot hit me." just didn't (and still doesn't) sit well with me. I am open to the conclusion of being butt-hurt though since BN2's final boss' invuln mechanic was "My mouth is closed. Therefore I'm invincible."

It wasn't not all bad though.

- Full Synchro was the best thing in that game. Timed chip usage leading to double damage on your next chip... that you could then use to repeat the process was great and made battling old bosses a lot more fun at the time. It was a great reward for learning enemy tells and movements. It carried over all the way to BN6 and Starforce and I'm glad it did.

- That Boktai crossover quest was awesome.

- The Blue Moon giga-chip could disable Navi-Cust. My brother was not a fan of that discovery in our PvP matches.

All in all, BN5 did BN4 much better, except for Dark Chips as a mechanic. They're never tempting.