Great premise for the game, I enjoyed shooting fireballs for a while :).
I can accept the no left or right for the path walking phase, but when it goes top camera and waves mode (nice mix of set ups there, I liked that a lot), then there needs to be left and right for the player to dodge. You can then balance this by giving the player MORE enemies to fight.
If you're continuing and processing the game, I'd want to learn more spells, and have a need to use them vs different enemies :), but it's a great job getting this game as far as it is in 2 weeks! well done!