Zero 3 definitely does away with a lot of the dumb ideas that held back 1 and 2, and it also doesn't have as excruciatingly terrible level design as those two. Even the soundtrack is almost listenable (Zero 2 is just
offensive to the ears at times).
It does share one of the biggest offenses of the series though, that remains a constant throughout all four games - there are so many parameters to twist in terms of powers and difficulty, that starting out on the game is going to be extremely overwhelming.
I think this does adhere to the themes of the Mega Man series as a whole, with the boss powers originating in MM1, and E-tanks in MM2 being standard bearers on the subject of a dynamically adjustable difficulty, built into the game entirely for the player's own satisfaction.
But the Zero games are just all over the place. I think there are potentially a lot of fun dials to mess with if you really get into the game, and plan on replaying it over and over. But if the game doesn't have a solid enough foundation I don't think it can really carry that, and all of the games definitely come short of that, at least compared to any of the original MM games, and the first four X games.
This design also means that the first few stages you play can be really difficult, with the rest of the game being much more of a pushover, which isn't an ideal structure for an action game.
- You have four different weapons, but only two can be equipped at a time, making it more frustrating than fun when the game expects you to rely on a specific one for a certain challenge.
- Beating certain bosses unlocks elemental attacks, which certain other bosses have weaknesses to. Classic Mega Man stuff, but for the entire series you get only the same three elements repeated in each of them, and the weaknesses are always the same. I actually probably like this more than the traditional boss weakness formula. There is no reason for robot master weaknesses being a "secret".
- Reusable subtanks can be collected, similar to the Mega Man X games.
- Extra body chips are unlockable in this game, and I'm unsure exactly what triggers them. At one point I got one after beating a boss, reloaded and beat it with a better ranking, but got a
worse chip. These chips do stuff like double jumping, auto-charge etc. Especially the latter is invaluable IMO, as having to holdi down the charge button constantly is one of my biggest gripes with both the X and Zero series.
- By beating bosses with an A rank or higher (the ranking being not for the individual stage, but a continuous average - so you can't just skimp on one to do well on the next) earns you EX skills, which add to your arsenal with a few of them making you quite powerful without hurting your rank.
- Cyber elves is the big thing for the Zero games, and they are always implemented in confusing, unintuitive ways. They work as either consumables or permanent upgrades, and are a finite resource that can only be used once each. They also serve as the game's attempt to scratch the Pokemon itch of collecting them all, which I don't think suits the Mega Man formula well, though they manage to keep that aspect inoffensive.
Using them liberally will make you absurdly overpowered, but using even a single one will hurt your rank permanently, which is where this customization aspect of the series starts getting really schizophrenic. There's no single "correct" way to play the games, and either way you go with will have you completely ignore extremely fundamental elements of the game's design. In Zero 3 at least you're allowed to upgrade certain elves to "sattelites" which means you can use their ability with no punishment to the rank, but the downside is you can only equip two at a time. This is a decent idea, but streamlined much better in Zero 4.
- Finally(?) Zero 3 also introduces "cyber space" which basically just means you play a green version of each stage segment between the bosses in which your cyber elves are made much more powerful, making them power you up even further, but the downside of doing this is another hit to your stage rank. Another aspect that's more streamlined in Zero 4's "weather" system.
Anyone who already hates the powerup shop introduced in MM7 will definitely have their hands full with everything offered in the Zero series.