Midnight Mansion HD
Midnight Mansion HD is a huge retro styled platformer with 11 different themed mansions to explore. Each mansion offers dozens of nicely designed rooms with treasures and keys for you to collect (and enemies and traps to avoid). The detailed map is also pretty nice because it shows you all rooms at once (including keys, doors and enemies).
The game is available for Windows/Mac and the game is pretty big as already mentioned (The demo alone takes already around an hour to finish).
Download (17$ / Demo available)
Note that the installation of the game takes around 5 minutes. (Many small files to copy)
Home Sheep Home 2
Home Sheep Home 2 is a charming single screen puzzle platformer where you have to guide three different sheep (small, medium, big) through various landscapes. Collect socks and make use of your environment to solve the puzzles.
If you want to see how the game looks in action consider to check out this video walkthrough that shows the entire “Lost in London” episode (which can be played for free online).
Play Online (1 Episode)
Download (10$ / HD Version with 3 Episodes + Bonus Content)
Photonstorm was involved in the development of Home Sheep Home 2 and has also written a comprehensive article about the creation of the game. He has also created Cat Astro Phi (a charming top down action adventure with Game Boy graphics)
Trine 2
Trine 2 is an amazing physics based 2.5D platformer where you control three different characters: a wizard (magical powers to move objects), a knight (sword & shield) and a thief (grappling hook & bow and arrow). Beside local co-op the game also features online co-op for up to three players.
Download (15$)
Serious Sam: Double D
Serious Sam: Double D is a platform shooter that allows you to blast huge amounts of enemies away by using up to 6 weapons at once via the Gun Stacker system.
Download (8$ // Free Demo available)
Blocks That Matter
Blocks That Matter is a clever puzzle platformer where you control a little drilling robot that collects blocks of different matter (sand, wood, stone, obsidian, iron, diamond) and recycles them into pieces of 4 blocks. If you create a line of at least 8 blocks you can press a button and *Woosh* they disappear like in Tetris. Beside the 40 levels that are offered in the Adventure Mode you can also create your own levels or play those of others.
An overall really enjoyable puzzle platformer that is available for Windows, Mac, Linux and XBLIG.
Download (5$ // Free Demo available)
Consider to watch this 2 min walkthrough of level 10 in order to see how the gameplay is.