I've beaten this game many times now and played all the branching missions this game has to offer. This game is in my top 3 for AC games on the PSP. The level of customization in this game is astronomical. You can really build the mech of your dreams here. There's incentive to get S rank in all the missions to get hidden parts. If you play on PSP there's even more parts to customize with. Yes. This game is difficult. It's a game that feels like you know how the mechanics and formula is already. This game tests all of your experiences as if you've played the previous games. It's a challenging yet rewarding game. Some missions however, come at you really hard even really early into the game. Most new players will find themselves throwing their controllers at the screen in frustration over their first AC duel they fail over and over. Human plus isn't in this game for the player unless you go the emulation route. Despite the curveballs, this is still a fantastic Armored Core game with very high replayability. The only thing I'd really change is how hover leg builds are treated. You see, this game introduces real AC damage. You can lose arms, heads, and cripple your ACs legs. The hover legs in this game break very easily compared to any other leg type. While I understand the developers did this to balance combat, they're far too weak and make building hover leg ACs (in this game at least) an obsolete option for many of the more challenging missions and during one on one duels against non-hover ACs and boss battles. They should have the same health points as say standard bipedal or reverse joint legs or have their hitboxes adjusted. You can still get by in the game with hover legs, but you'll need to build accordingly and be skilled enough to evade attacks in all of your encounters.

A bit unfair at times but still good fun. The customization is on point, the gameplay feels great, and it's challenging without feeling frustrating.

This game is great on it's own without any other titles in the series. Every part from the 3rd generation can be unlocked here, so if you love (well hidden) Easter eggs, this game is loaded with them. It's also the first game in the series with decent voice acting. It's very difficult until you understand the mechanics, so if you are not a masochist or god gamer, this might not be for you. There are ways to fool the AI that would not work against real players, but the trick isn't very obvious and still requires skill (and a high speed build) to implement. 1v1 combat with other players can get pretty deep. It does have many "useless" parts that I wish had some application, but once you find the right recipe, it's satisfying to play. I think giving it a "10" is way too generous, but I'm doing it anyway.