A lot of fun, only a few suggestions
This game was very fun with an easy learning curve. This game brought back memories of NFL Blitz.
If you every make another version of this, or any adjustments, I would highly recommend a statistics engine for individual players (goals, games played etc.), and perhaps eliminate the (unintended?) ability for the player to skip past the season-begin trade screen, then go back to main menu in in order to reshuffle the list of available players for trade (this made it much easier for me to form the best team early, where I think I might've had more fun having to really work for the wins through the season with only the players that I COULD acquire).
Only other suggestion is a reiteration of what at least one other member said: create separate keys for tackle and shoot. Also, perhaps add a direction arrow on the player with the ball so we know where the ball will go if 'throw' is pressed. Oh yeah, one last thing: maybe add a red ring or something around the selected player when they have the ball--there were times when I thought I still had the ball and stood in front of the goal pressing shoot rabidly, only to realize it had been stripped of me. Terrific job.