Age of Canterlot

Edit: the first sentence is somewhat mistaken, so please disregard it if you will.

Ponyventure

Island of Falling Stars

Magic Hexagon

 As can be gathered from the game's announcement on Tumblr, Magic Hexagon is basically an open source clone of Super Hexagon with pony cutie marks, placing it under the "barely pony related" category. There's not really much to offer for feedback here without either essentially reviewing the original or commenting on the developer's taste in libraries/programming languages, although it would be nice to have some more variety when it comes to songs (the creator is looking for a musician though, so that might be resolved in the near future), along with pre-compiled OS X and Linux binaries in the near future.

 In case you're interested in contributing to the project or compiling it yourself, you can check out Magic Hexagon's GitHub repo at https://github.com/meh2481/magichexagon.

Luna's Letter

 Jach Marsdonpone (primarily known as the developer of No Guns in Canterlot and A World You Should Not Know, now a member of Silly Mare Games) decided to make his own entry for the marathon, and it basically came out as a more boring version of My Little Hang Glider. You float like some kind of really fat duck, touch colourful balls and fly past the occasional incoming projectile with your boost (the aforementioned floatiness prevents you from simply dodging them like in most games). Also, those pretty clouds? They constantly obscure your vision and the interface, rendering the latter almost utterly useless a lot of the time.

 So...yeah, it'd probably be for the best if you skipped this one. Jach's other games are much more entertaining (even if they aren't quite as pretty as this one, which I'd say is probably the most visually appealing game in the marathon), so why don't you try them out instead?

Lyra and Bon Bon Save the World

Celestia's Cake Golf Adventure in Space

 I was pleasantly surprised to hear that futzi01 would be participating in the MLGD marathon; this odd little game of interplanetary golf is probably one of his better recent creations (most of which were unfortunately a tad dull). It starts off well enough and introduces some interesting gameplay mechanics as it goes along, but suffers from a massive difficulty spike partway through the game that would make bring the chosen undead to his knees. This probably has something to do with the game's being created within several days and there not being too much time for playtesting, so it's still pretty impressive: just don't expect a superbly polished experience.