I've beaten this game on the X360, the PS3, and on the PC. I've gotten everything from the in-game slot machine. And it is glorious. This game is a solid arcade-style shooter like Binary Domain or Vanquish and gives you a veritable arsenal of weapons to fight off a large variety of enemies. The dialogue is somewhat cheesy, but it fits the tone of the game since it doesn't try to be a "war is hell" shooter ot take itself too seriously. C'mon, you can even set a variety of emotes like waving, dancing, or even crotch thrusts! Most everything the enemies do or characters in the cutscenes can do, you can do.
Want to grapple on to a giant arthropod and shoot its glowing spot for massive damage? You can do that.
Want to use a VS [basically mechs] that you saw a boss use? You can use it at some point in the story.
Want to shoot a giant spider in the face with a laser? You can do that too.
Want to fuse two VSes together to make a super-VS to kill everyone around you? You can do that.
Want to use VS weapons while on foot to blow someone across the room? You guessed it, you can do that!
The game gives you a set of default weapons, and you unlock more through an in-game slot machine using in-game currency. If you don't want to do that, then you can unlock a number of weapons, character parts, and items through levelling up your character in Campaign. You have a variety of game mechanics at your disposal to fight your enemies. You've got a grappling anchor you can use to latch on to enemies and you aren't only able to use it in a single stage, but rather it's available throughout the game in every stage. You can shoot grenades to blow them up in a larger explosion, or just use another type of grenade like the Gum [sticky] grenade to fight your foes off.
Most of your foes are large insects and invertebrates called Akrid. They also happen to have giant glowing points along their bodies, such as their limbs and abdomens. The first large Akrid you meet in the campaign has weak spots on its arms that you can use to blow them off. The Akrid will regenerate their limbs over time, but I reccomend just blowing them off again! On other occasions, you get to shoot people in the face.
The human enemies have access to most of the same primary weapons as you do, like the Energy Gun and the variants of the machine gun. They'll also occasionally use VS weapons, in which case they will probably become one of your primary targets.
While you can't pick up a dead enemy's weapon, there are a variety of weapons scattered throughout the level. All of these weapons match what you've selected in your character customisation, which helps when you want a particular style of weapon. If you happen to play the co-op, then the items appear as whatever items the host has set in customisation. The game keeps up a constant flow of action by continuously throwing pre-placed enemies that will run around the area in a futile attempt to survive. While their durability varies based upon which of the three pre-unlocked difficulty settings, so do the weapon and armor placements. For example, I played the first few stages on Normal and found the usual VSes and weapons, but playing it on Normal scattered a number of suits of power armor that you could use around the early levels.
All of this helps to show the level of work put into making this game enjoyable, and in my opinion, they succeeded at making a good, engaging game. I'd wholeheartedly reccomend it to anyone looking for a good shooter that you can jump in and out of if you're busy or play in co-op with someone else.