Your feedback is heard! There has been some confusion about how the gameplay actually works and what the "triggers" for jumping are. Therefore, here are the improvements that are out there now:
the tutorial got better;
the game now detects if you have completed the tutorial and if not, prompts you to take the tutorial (although still completely optional);
store page descriptions are updated to be clearer.
Remember that "Jump If You Can!" is a heavily timings-focused game! YOU get to figure the best moment to attempt to jump, based on the current phase in relation to the timer messing with your jumping ability (by turning it on and off, making it increase/decrease, etc) and the next platform cycling between going left and going right.
Happy Jumping!
NEW OS Support: Linux
"Jump If You Can!" is now available on the Linux platform (aka GNU/Linux, which it technically should be referred to), so if you've been waiting for "Jump If You Can!" to be available on Linux, wait no more! For Ubuntu, the minimum version required is 14.04 LTS 64-bit with all the updates (so that libstdc++6 has received the required updates); minimum recommended version is Ubuntu 14.10 64-bit. As far as other system requirements, those are quite the same as for Windows, i.e.:
A 2 GHz processor or faster
1GB RAM
100MB free storage space
An OpenGL-compatible graphics card that supports at least OpenGL 3.0, although OpenGL 3.1 or higher is suggested