Good, But Spice It Up!
While not being a technical or artistic achievement, this is an innovative game... once you use a password to see all of the extra levels. There are several things that can be done to make this game world-class and also hold players' attention longer.
Two fundamental problems with this game exist as one: the lack of variety and lack of innovation in early levels. Moving gaps, moving, rotating, and spinning platforms, pathways whose borders flicker on and off in the dark, and sections that disappear and reappear create a very high innovation potential. The lack of creativity in the employment of these obsticles creates the mundaneness and monotony which I suspect is behind the so-so voting and average review scores.
One significant drawback is the fact that the player doesn't even encounter any of these advanced obsticles until level 6! This leads players who are frustrated early on to believe that there is no further value to the game and give up. A second drawback, almost as significant, is the fact that levels 6 and up have only one special obsticle kind apiece, a decision which, besides causing the game to fail to live up to its gameplay potential, also limits the number of levels possible without redundancy.
A much better approach, once the early abacadarian levels are out of the way and the player understands the objective, is to slowly introduce the special obsticles one at a time, finding creative ways of integrating these with the static paths, and later causing different kinds of special obsticles to interact with both the static paths and each other. This will greatly expand playability and end user interest by: 1) creating anticipation of what kinds of special obsticles lie ahead, i.e. "What will he think of next?" 2) creating anticipation of seeing unique ways that these special obsticles interact to create a challanging patch, and 3) making the number of possible levels and challanges nearly infinite. Under these circumstances, even players who "cheat" by using a password to see all of the levels might, if the levels are designed well, still want to play them anyway for the fun and challenge.
That is only really major shortfall of the game that needs to be improved. On the minor side of the equation, more variety in the area of graphics and music would also be helpful. A game like this doesn't need fancy visuals, and the art style that's been chosen suits the game perfectly; but again, the problem is variety. More (and some brighter) color schemes and the addition of varying background animations would add a lot of life to the game. The biggest problem visually is when the player loses the game; some kind of creative transition animation (any kind really) would be so much better than simply cutting to the game over screen. And, at present, the player is forced to put up with the same background music for nine levels; more background tracks would be very welcome.
I want to congratulate you on taking a simple idea and making it innovative; I think that, with a few improvements, I seriously think that this game could go from good to world-class.