I hate boss rushes in Mega Man games. In the classic games it’s fine 
enough since the bosses die in 3 seconds with their weaknesses and their explosions are just as long, but the X and Zero games drag it out so much. First you have to sit through the warning notice if it’s X4 onward, then the boss does an intro (in Zero games they have dialogue as well but I actually read it since it’s interesting), then the actual fight is extended by their i-frames, when you kill them they have a long explosion (in some games it’s 15. Seconds. So 2 minutes of the entire thing is spent on explosions), then you teleport back. Rinse and repeat 7 more times. I can tolerate it in Zero because the bosses there can still be fun with weaknesses, and a few don’t have any, so it does feel like a challenge. Kind of. But with weaknesses in the X games, they just devolve into brain dead spamming. People defend these by saying that it lets you see your player growth, but that makes no sense. In almost every Mega Man game, weaknesses are win buttons against 80% of the bosses (which isn’t good boss design). The only growth here is if I didn’t use the weakness against the boss initially, but otherwise, there was no chance of losing the first time and there’s no chance of losing now. It doesn’t get me any more excited to beat the either; it’s just blatant padding.
The way Mega Man 1 and X1 do it makes it less tedious by not locking you in a room. It’s annoying enough when they put you in a room with capsules, but the worst kind is the one where the boss rush is the same level as the final boss. 7 is by far the worst capsule one like that since they admitted to making the Wily Capsule 7 “insanely hard.” Mega Man 8.5 does it similarly to 1 and X1, but somehow manages to create one of the worst ones in the series because it puts it in the same level as the final boss. I feel like it’s a case where the game’s difficulty goes a little too far, and it still feels like padding since it’s all done in one stage. In the X games, X5 is easily the worst I’ve played so far. It’s in the same stage as the final boss, but for some reason they also decided to give every boss 3x their normal health. You’d think that making the bosses stronger in the boss rush would make it feel less like padding, but these are just the same exact fights except you spam Nova Strikes/weaknesses for longer, so nothing changes other than it being more tedious. I can’t fathom who in their right mind would have found this fun. The only thing I like about this stage is how it has 
rave music playing after the mysterious and somber track given to the first three final stages. X/Zero just had to fight their best friend, and now you’re about to fight Sigma but first you get to listen to club music. It’s so unfitting that it’s funny.