The first thing you'll notice upon starting Outland is just how damn good the visuals are. The art style is fantastic - the ancient scenery and the way the silhouettes in the foreground contrast with the lighter background is very striking.
Then you'll realise just how smooth and responsive the game feels. The controls in Outland are just right, and it has buttery smooth animation to go along with it. It's as good as 2D platformers get.
The whole switching between light and dark essence thing works wonderfully too, and mastering this ability and swiftly solving various challenges and puzzles provides some unexpected but enjoyable challenges. Swapping between light and dark as you dart through various colour-coded traps may prove a little difficult at first, but time your switches properly and you'll feel like a complete bad ass when you pull it off.
Speaking of challenges - the boss fights here can be very hard, but the bosses all have tell-tale attack patterns, so once you figure out the correct technique, it's all about tight execution. If you're looking for some extra enjoyment out of the game you can also take a crack at co-op.