I really love the game and I am thinking about running it, the only game I tried to tun so far was portal but I didn't really have much fun with it I was thinking either I will run Battleblock or hitman Blood money. How hard is this game to learn?
This was my first speedrun as well. All I can say is that there are many strats, but they are straight-forward. There's nothing too complicated or too game-breaky.
We can help you a lot on our discord: https://discord.gg/QbRzwrb Besides discord, you can watch the WR run and learn through there.
I think any game you enjoy can be a good speedgame. If you enjoy it and want to speedrun it, go for it.
Also, if you want to start a bit smaller, you can speedrun challenge mode at first, then when you are ready start going for the full game.