First of all - please, please don't mix mouse and keyboard controls unless necessary, especially if the keyboard controls involve anything more complex than arrow keys/WSAD. It's a pain to switch to mouse just because menus don't do keyboard. >.<
Second - I wonder where all that filesize came from, since the game itself seems rather simple and I don't see too many assets or special graphical effects, either. O.o'

As for the game itself, there's quite a room for improvement. In the upgrade screen, I'd really like to see the exact parameters and how they'll change depending on the upgrade. So e.g. it's not just "Reduce Earth Cooldown", but rather "now the cooldown is 5 seconds, but for that upgrade point it'll reduce to 4.8", that sort of feedback. As for the gameplay itself felt rather clunky for some reason, and I kinda just wanted the levels to be over already. Also, I really don't like the tendency for levels to become longer and longer; prolonging time to survive usually just makes things tiresome rather than challenging; maybe just stick to making enemies stronger with each level instead? I liked that there were a few kinds of enemies, but it wasn't enough to keep me really entertained, sorry. ^^' Oh, also, it'd be really nice not only to have shown whether a spell is in cooldown or not, but also how much cooldown is left (e.g. by gradually filling the elemental change indicator or such).

I found the graphics to be a tad too simple for my taste, and the music seemed to go on really chaotic; like it was different tracks pasted together rather than one coherent piece. That might require some work, too. Another thing - the menus were bugged; i.e. after a game over I restarted and the buttons stayed there or something.

Overall, keep working and learning, there's some way to go. ^^'

Creative idea, how you don't have weapons per se, but using the elements to transform yourself can attack enemies. I like it! The difficulty curve is pretty good. I was able to last for a few rounds before finally succumbing. I like the fast pace and the upgrade mechanic. Introducing the elements one at a time would have been helpful. It's pretty much impossible to know what you should upgrade first when the screen first appears. But I still had fun. Oh and thanks for the Linux version! :)

I would give you a good rating just for making a Linux version (thank you), but the game is also fun.

Managed to get score of 129. There's something broken with fire (probably), since if you max it, you actually heal instead of taking damage! Overall, not bad!