If you take the "short 15 levels" games developed by Eddynardo, you have 5 of those on the site: Choppy Orc, One trick Mage, Sticky Sorcerer, Greedy Mimic, and now Hasty Shaman. (Dozenbear by eddynardo doesn't count because it is a different genre)

While the concept of games with lot of short levels isn't new (There are plenty of them on the internet, even from the Flash era), those games by eddynardo had a great success on Kongregate and Armor Games, and it inspired several other developers to make games with similar concept (Lot of short levels, usually between 15-30, with a puzzle-platforming element).

Several games like that which I speedrun, and the developer openly stated it was influenced by eddynardo: A Pirate and his Crates, Overlord's New Mansion, Fireblob and Fireblob Winter, Start Powerless. There are several more games which I ran and are not on the site, mostly by developers Noadev, Junjo, Jronn.

Now, for your question - whether if you asked specifically about games by eddynardo, or similar games in general; Those are great games to speedrun, for several reasons:

• They are relatively short, so you can do a speedrun in a few 1-4 minutes without investing lot of time.
• You can stop running whenever you want.
• Most of the games have a beginners route and experts route, where the "experts" gradually use more tricks and glitches into their runs.
• There is no filler time, you start a new speedrun and you start right away with the action.

For your second question, you just need to open and play the game in many of the dozens game sites out there, a google search can find it quickly. I usually stick to Kongregate, Armor Games or Newgrounds.

Those double jumps only exist in Choppy Orc and One Trick Mage, thankfully. The other games have different tricks, and here (Hasty Shaman) you have teleport jumps.