Here are 50 new levels starring the chubby cat-cherub duo and by extension, their overworked fletcher back home. Move and jump with the [arrow] keys and fire with the [space] bar (use [WASD] and [F] if you're the other player). Perforate adorable blobby creatures of all shapes and sizes with an unlimited supply of arrows, and then collect the loot they leave behind and fly to the next level. Rinse and repeat till you face one of the best Nitrome bosses in recent memory, and then it's time to go to Hades for Round Two, and another 50 levels.
The catch is that the second group of levels (the "Evil" levels), aren't free. This is Nitrome's first experiment with micro-transactions (YES micro-transactions in FLASH games... thanks nexon! F5), using the new MochiGames system. This is something you're going to be seeing in a lot of games soon, so now is as good a time as any to make an account. Much like GamerSafe, MochiGames is a way to keep your high scores and progress for a game saved in a central location, so you can access them from any computer. It also lets developers offer premium features for a small fee of MochiCoins, which you can purchase using real money or by completing tasks in certain games.
The Evil Levels in Twin Shot 2 feature a whole new cast of enemies and several new gameplay ideas, such as blocks you can push around to reach higher places, or spiky monsters that won't die until you bully them onto a bed of hot coals. It's nothing more than 50 more Twin Shot levels, but if you're a fan of the game, you won't be disappointed. They'll run you 3000 MochiCoins, or about $3.75 US under Mochi's current pricing. For another 1000 MochiCoins, you can buy a suite of cheats and extras, including a fun secret character from another ancient mythology-based Nitrome game and a cool Random Level Mode that includes the original Twin Shot levels and even some extra levels that you won't see in the main game.