For a first game:
A lot of this looks hand-drawn. For example, the computer mouse at the beginning of the game looks like it was drawn by hand. That just gives a weak impression to the game player.
The platforms the player is running on are also random. Look at Super Mario Brothers, for instance. They are very rectilinear and run at right angles or parallel to each other constantly throughout the game.
The sound quality is poor.
I don't have a strong opinion about what language you use, but some people do. If you're going to use Spanish, (which is fine), you may want to *also* offer English in a menu option to market to the more international environment of the Internet.
Good luck. If this is your first game, then you're doing great. Don't be disappointed.