Syntorial 2 Velocity In Randomizer Challenges

Hello ! I finished Syntorial 2 Lessons and wanted to try the Randomizer Challenges...
Now, typically I would solve challenges by playing the pre-defined pattern or using the "QWERTY" keyboard option.
The problem being that when it comes to Velocity, I would rely on the pattern being played to see and guess the kind of modulation happening...
Having only the computer keyboard as an option in the Randomizer challenges, there's no easy way to control the velocity therefore making the experience pretty frustrating...
I don't feel like plugging a midi keyboard each time I play Syntorial ( at least in my current setup ), is there a solution for my case ? something that I don't know ?

Thanks for your help and suggestions !!
Pierre