Pretty neat. Above a height_level of ~430 you cannot see bright cubes anymore because of the bright background.
I would rather use event_impact (and player.z > block.z) instead of hundreds of while loops. I would make the blocks disappear after the player jumps on them to increase tension. If you realize both suggestions, make sure no two consecutive blocks are directly above another, otherwise you probably cannot make the jump.
Additionally, I would replace the *time_step multiplications as follows:
jump -= 1.6 * time_step;//has to be time corrected
jump = maxv(jump,-12);
...
c_move(my, nullvector, vector(0, right_left*time_step, jump*time_step),...
...
jump = 47;


Your game has given me an idea:
Why don't we users create small game examples like the one you've posted (maybe improve it a little) that get shipped with future Gamestudio releases/ updates? I think the current samples folder lacks some real playable games.
The reward for the creator could be fame and some cheap advertising, f.i. displaying a link to his own website.