The Zero series is probably my favorite game series (or subseries) of all time. The sense of speed and just overall badas$ery is unparalleled. On top of the amazing gameplay, the series also has a surprisingly good story, especially compared to most other Mega Man games. The inclusion of the ZX games in the collection is just icing on the cake.

Zero 1: Yes, it has screen crunch. Yes, instant death can be incredibly frustrating (looking at you, Protect the Factory). But I still just love this game. Once you get past the grinding, the rest of the game is a lot of fun. This is the game in the collection I've played the most, except maybe Zero 3.

Zero 2: Honestly just a really good game. Great gameplay, great story, great level design (for the most part). It There's some segments with frustrating design, but overall this is just a big improvement over Zero 1, aside from less replayability.

Zero 3: This is probably my favorite game of all time. The bosses and level design are incredibly fun. This game also perfects the Cyber Elf system, letting you feed and switch between them at will. Another great feature in this game is the Recoil Rod. Bouncing off of enemies and forcing them away is incredibly satisfying, and adds to the sense of speed that is the core of this series. And the story is phenomenal, with multiple twists and turns and emotions throughout. I can't recommend this game enough.

Zero 4: I've only played this game once. For comparison, I've played every other game in this collection other than ZX Advent at least twice. I honestly just hate this game. The graphics are appealing as ever and the core gameplay is still there, but it just doesn't feel like a Zero game. The level design is frustrating more often than not, and on multiple occasions I felt like I just wasn't enjoying myself while playing the game. The story isn't much better. The focus shifts away from Zero, Ciel, and the Resistance and towards these new OCs, who bring their own backgrounds and relationships with them. The only thing I enjoy about the game is the final boss and the ending itself, but it's sad it's tacked onto such an otherwise disappointing experience.

ZX: This game has a lot of good ideas. The different transformations are fun to use and experiment with, and the bosses and levels are fun. Where this game starts to become a drag is the time between levels. The grinding from the Zero games is gone, but at the price of having to walk to each level. You're practically required to look up a map online because the game gives you so little direction. Even with a map available, the time it takes to travel to each level kills the pace of the game. Other than the time-wasting, the rest of the game is a lot of fun. The best thing about it other than the freedom of movement provided by Model H is the secret boss fight, which is probably my favorite fight in any game.

ZX Advent: I've only played this game once, and I honestly don't remember all that much. The gameplay is still fun, and the drag of walking between levels is mostly fixed with an actually reasonable fast-travel system. The level design is a bit worse than ZX, but I feel like I enjoyed the experience for what it was. Overall, just okay.

If you were to skip any games, I would recommend playing the first three and skipping the rest. I would rank the games:
Zero 3
Zero 2
Zero 1
ZX
Zero 4
ZX Advent

Overall, I would say it's worth the buy.

The Zero series is probably my favorite game series (or subseries) of all time. The sense of speed and just overall badas$ery is unparalleled. On top of the amazing gameplay, the series also has a surprisingly good story, especially compared to most other Mega Man games. The inclusion of the ZX games in the collection is just icing on the cake. Zero 1: Yes, it has screen crunch. Yes, instant death can be incredibly frustrating (looking at you, Protect the Factory). But I still just love this game. Once you get past the grinding, the rest of the game is a lot of fun. This is the game in the collection I've played the most, except maybe Zero 3. Zero 2: Honestly just a really good game. Great gameplay, great story, great level design (for the most part). It There's some segments with frustrating design, but overall this is just a big improvement over Zero 1, aside from less replayability. Zero 3: This is probably my favorite game of all time. The bosses and level design are incredibly fun. This game also perfects the Cyber Elf system, letting you feed and switch between them at will. Another great feature in this game is the Recoil Rod. Bouncing off of enemies and forcing them away is incredibly satisfying, and adds to the sense of speed that is the core of this series. And the story is phenomenal, with multiple twists and turns and emotions throughout. I can't recommend this game enough. Zero 4: I've only played this game once. For comparison, I've played every other game in this collection other than ZX Advent at least twice. I honestly just hate this game. The graphics are appealing as ever and the core gameplay is still there, but it just doesn't feel like a Zero game. The level design is frustrating more often than not, and on multiple occasions I felt like I just wasn't enjoying myself while playing the game. The story isn't much better. The focus shifts away from Zero, Ciel, and the Resistance and towards these new OCs, who bring their own backgrounds and relationships with them. The only thing I enjoy about the game is the final boss and the ending itself, but it's sad it's tacked onto such an otherwise disappointing experience. ZX: This game has a lot of good ideas. The different transformations are fun to use and experiment with, and the bosses and levels are fun. Where this game starts to become a drag is the time between levels. The grinding from the Zero games is gone, but at the price of having to walk to each level. You're practically required to look up a map online because the game gives you so little direction. Even with a map available, the time it takes to travel to each level kills the pace of the game. Other than the time-wasting, the rest of the game is a lot of fun. The best thing about it other than the freedom of movement provided by Model H is the secret boss fight, which is probably my favorite fight in any game. ZX Advent: I've only played this game once, and I honestly don't remember all that much. The gameplay is still fun, and the drag of walking between levels is mostly fixed with an actually reasonable fast-travel system. The level design is a bit worse than ZX, but I feel like I enjoyed the experience for what it was. Overall, just okay. If you were to skip any games, I would recommend playing the first three and skipping the rest. I would rank the games: Zero 3 Zero 2 Zero 1 ZX Zero 4 ZX Advent Overall, I would say it's worth the buy.