The first Rengoku game was the single worst launch game for the system. A repetitive, ugly, and boring mess I'm surprised Konami approved a second game at all. You control A.D.A.M., a battlefield AI android. The story is based on The Divine Comedy, but it's so poorly told that you won't care. Cut scenes are minimal, consisting of a few lines or walls of text over drawn backgrounds. Cut scenes are infrequent, typically occurring only before or after boss fights and upon reaching the next floor. The bosses' names reflect the Seven Deadly Sins, which are represented by seven floors. It's a throwaway concept and half-baked.
The most surprisingly decent part of the game is the controls. Combat consists of running around boring and claustrophobic corridors. The game only introduces color near the end. Fortunately, you receive a map that highlights all the rooms you have yet to visit. Each room locks its doors until you defeat all enemies. Your body attaches weapons to specific parts. You can attach weapons to your arms, head, torso, and legs. These can range from ranged to melee weapons, heavy and light; some you hold down, like the chainsaw, and weapons like the hammer do heavy damage. You pick up weapons by defeating enemies or finding them in capsules. These body parts also correspond to each face button. This is a unique and cool concept, and while the game forces you to do different combos to increase damage, the animations and feeling of the combat don't reflect this. It feels like you are fighting with a four-armed octopus instead. Your android floats around the levels in a Naruto run, and once you lock on to an enemy, you just wail on them, as there's only a dodge feature (double tap on the analog nub). You also need to watch your heat meters for each body part, as holding down the button too long will temporarily disable them until they cool down. The issue can be remedied with upgrades. Health will regenerate at all times, which kind of helps.
The game relies heavily on grinding out "skin," which is used to upgrade everything. You can enhance your health, defense, heat, and more. Extra skin is dropped from "overkilling" enemies. When you defeat them, their green health bar will turn red. Fill this bar up with more hits to get more rewards. I honestly felt the drop rate just wasn't high enough, as the first boss required me to go back through the same boring hallways and kill enemies until I got enough skin to withstand enough attacks to beat the boss. The worst part about the combat is the knockback effect. You can't cancel it out, and it's difficult to tell whose attacks are landing. The animation feedback doesn't really exist unless the enemy actually falls down. The combat is stiff and cumbersome, and when you're knocked back, you break your lock. Thankfully, you can press the L button at any time, and the camera will swing around and lock on. It's a great lock-on system, and it's too bad it's attached to such a terrible combat system.
In theory, this combat system sounds excellent on paper. It just needed more time for better animations and polish to feel fluid and fun. Every so often you will find warp points that can bring you back to the floor's terminal, in which you can save and upgrade. When you die, you drop all of your equipped weapons and must return to retrieve them, which adds a Souls-like aspect to the game. You will accumulate so many weapons that you won't need to worry about running out. Weapons also have "ammo," and after so many uses, they won't work. You will default to that part's bare melee combat. You can upgrade your slot count, but it’s expensive, and you can have five slots per part. Once you run out of ammo for one part, it will auto-switch to the next.
Regrettably, we could overlook this if the game had improved in terms of appearance, sound, and feel. The graphics are unattractive, featuring small and cramped brown corridors. Every room features identical metal boxes and damaged walls. The enemies all look generic and the same. The only things that change are the bosses. The music consistently plays the same terrible techno track, causing your eyes and ears to ache after prolonged exposure. If you like grindy games and conquering room after room, you may enjoy this.