Level Up (not the trope) is a platformer in a vaguely similar style to Achievement Unlocked. The Girl has to explore her world and level herself up in order to help The Boy that recently crash landed in her backyard. She can only stay up for so many hours before she has to return home to sleep.The game is available at Newgroundshere.
Tropes used in this game include:
100% Completion: Doing so unlocks a demo of the sequel, Gather Up.
It's actually The Girl whose past is truly dark and troubled.
Elves VS Dwarves: The Squarians versus the Roundites, sort of. There's also a third race, the Hexies, who didn't want to participate in the feud between the other races, and moved as far away from them as possible.
Laser-Guided Amnesia: The Boy. It's so bad, many of his levels are sent to level zero. The Girl has a form of this that can only be fixed through the computer.
Level Up: Many things are leveled up, from taking damage to sitting around to leveling up.
Level Up At Intimacy 5: By donating gems to the Boy, you become more and more friendly with him, which increases the Girl's heart level, and in turn her life meter, for a maximum of eight hearts.
Meta Guy: Brains the Squarian; his metaness is even essential to completing your CODEX. He does have enough sense not to tell the Girl how the game ends, though.
Orphaned Series: Unfortunately, despite the first game's popularity, and the surprisingly good alpha builds of the second game, the game's creator was unsatisfied with where development was going, and "put it on the back burner" back in 2010.
Restart at Level One: This happens at the start of every new day with your levels. Averted with the sleep levels and any skills you have gotten. If you defeat the Nightmare that night, you don't lose your levels.
Fortunately, your levels regain a lot faster than if you'd just started the game on Day One.
Sudden Downer Ending: The game ends with the truth of The Girl and Boy's identity, which has a fight break out between the two. In an otherwise meta and comedic game, this is very jarring.
Tomato in the Mirror: The ending reveals that The Girl is actually a Dark Action Girl obsessed with power. She lost her memories when she tried to defeat the Deity, the most powerful being who had "surpassed levelling". The Nightmare is her subconscious, furious at her failure.