Half-Life 2 is a first person shooter, right? People make mods for it involving shooting right? So just how is it that someone makes a Half-Life 2 mod that is a platformer centering around a schizophrenic nutcase? I'm not so sure, but I'm glad they did, 'Flipside' is the most creative Half-Life 2 mod in every way, from graphics to art to gameplay.
'Flipside' is a mod made by Team 3, you play as Hanibal Hildorf, a shadow puppet suffering from multiple personalities, one in which he percieves the world as happy, another in which he sees the world as evil.
Changing between personalities is completely up to the player, As you jump your way through Hanibals world you'll find that you need to change between his two psyche's, Hanibal as evil cannot jump high but can climb walls and attack enemies, Hanibal as good can jump high and his 'enemies' are cutesy animals that push him around without dealing any health damage.
Both worlds are quiet imaginative, while trees may be nice'n'green on one side they are eyeballs on the other, a happy nurse bunny is an evil nurse bunny drenched in blood when viewed from Hanibals alternate personality.