Inferno 2+ is cheap, easy and fun gamerscore. It's well worth your time. Inferno 2+ is a classic shoot 'em up with a twist: Instead of an open arena, you fight through a variety of puzzles. You'll need to locate keys to open doors and bypass destructible wall or walls that open and close.
The shoot 'em up elements are strong, but uninventive. You'll have the usual types of enemies. Some enemies just follow you, some follow patterns and some shoot their own projectiles at you. You can choose and quickly swap among four firing patterns and four missile types. Depending on the difficulty you select, you might have a large or a small health bar. Two or more drones will follow you, firing as you fire, and sometimes taking hits that would have hit you.
Inferno 2+ also has some leveling mechanics. You earn XP for killing foes and gain upgrade points to apply to your weapons. You can also find upgrades in hidden parts of levels. This gives a fun incentive to search around the levels, rather than blindly finding the keys and racing to the exit. Best of all, the upgrade mechanics reward you for doing what's fun in the game; killing enemies and finding treasures.
The other part of Inferno 2+ is the puzzle-like levels. Most levels revolve around locating keys to get to the exit. None of the puzzles are especially difficult, but they provide an extra bit of fun. The obstacles and terrain make Inferno 2+ a different experience from the standard shoot 'em up. Often, you'll be able to see enemies massing in an area before you enter it and make a plan on how to approach. This gives Inferno 2+ a slower, more tactical pace than the standard frantic shoot 'em up.
There are a few downsides to Inferno 2+, however. As I mentioned above, the puzzles are simple, sometimes to the point of being dull. Bosses are extremely basic. Nothing here is innovative. The game is short, about 30 minutes to complete the achievements and 1 hour total.
The achievements are extremely easy. You'll need to pay attention to how you spend your leveling upgrades. You can get all the achievements on the easiest difficulty, no problem.