Looking for a platformer that'll bend your brain a bit? AlterEgo: DreamWalker is the 8-bit-on-acid sequel to AlterEgo, and basically just builds on its predecessor. More levels, arguably trippier visuals, and the same switch-up platforming action of the original. The game mechanic, by the way, is simple, but fairly novel: you move your character around the platform world, but on the opposite side in a mirrored position as an 'AlterEgo' (the ghost-looking thingy).

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The alter ego doesn't take damage and can move through any obstacle, and you complete levels and progress by swapping positions with him at any time. Just watch the video - it'll immediately be clear what's going on.