[7] Within a Deep Forest / Knytt Stories
These games used to be pretty popular back in the day, but you never see them mentioned anymore. Both made by some Swedish dude called Nifflas.
Within a Deep Forest is a unique little platformer where you play as a ball and have to bounce around obstacles. It's a bit of a Metroidvania in that you slowly acquire more abilities that allow you to unlock new areas (heavy ball to break weak floors, glass ball to avoid triggering lasers, etc.). It's just really fun and well made.
Knytt Stories is a sequel to Knytt. Both are fairly basic platformers, but Knytt Stories' real selling point is the fact it comes with a level editor and quite a lot of premade content. There are literally thousands if not tens of thousands of levels made for it, and some of them are actually pretty good. People have done incredibly creative things with this game. Nifflas has unfortunately shut down his forums a while back so a lot of the content has been lost, but thankfully most levels were uploaded to
knyttlevel.com, which is still up and is somehow still active, despite this being a 15 year old freeware game.
Nifflas eventually released Knytt Underground, which is a paid game that quite literally combines Knytt with WaDF. You press a button to switch from a jumpy/climby humanoid to a bouncy ball, and that makes for some unique traversal mechanics I've never seen in any other game. Some old fans dislike the theme and scale of the new game, but I personally really loved it.
https://archive.org/details/Within_a_Deep_Foresthttp://egomassive.com/ks/https://store.steampowered.com/app/248190/Knytt_Underground/ 