Interesting... It's kind of like playing one of the earlier 2D adventure games like King's Quest, then being able to break out into 3D rampage mode.

Actually, that would be awesome for a game, start off as a point an click pseudo-3D adventure and become an first person scavenger hunt after a specific trigger point. Kind of like what "Evoland" does, but for FPS games, not RPGs. :)

You can try games that were somehow ported to phones or they were ported to PC from phones. Usually, games that work on phone kinda require exactly what you ask for. Easy to play it and abandon it pretty fast, and they are pretty colorful.

- Knights of Pen and Paper + 1
- Anomaly series
- Bridge Constructor
- Broken Sword series
- Frozen Synapse
- Worms
- Kami

Then, games that are not ported but follow the same idea.

- Ittle Dew
- Spelunky
- Dwarfs
- Monaco
- Bastion
- FTL: Faster Than Light
- Magicka
- Don't Starve
- Defcon
- Deathspank

Now, there aren't so many free games, but, most of these were in all kind of Bundles pretty often. So, you can usually find them pretty cheap. Why not go for something cheaper and more fun, like PSP or Game Boy Advance SP? I love my PSP, i play old NES/SNES and PS1 games on it, like Chrono Trigger, Xenogears, early Final Fantasy games, Secret of Mana.