This game is fantastic, the Egyptian environment just turned out great and the gameplay premise is simple but addictive!
I really like the graphics and style of your game, the desert hovercraft thing gets special mention, super cool with the gasmask guy manning the harpoon :) The particle effects really turned out well, I especially like the dust trail.
The gameplay feel is super satisfying and polished, especially with the music and sound effects (picking up gems and scarabs!) and I find it awesome that you managed to create a global leaderboard.
Kinda messed up on the 'story mode' the first time round (I got greedy) so it was a tiny bit frustrating to have to go through the tutorial again (really carefully this time, since I reckoned that 'chaos mode' would be unlocked). It would probably have been fine to unlock chaos mode directly on obtaining the 3 scrolls, in my opinion.
Other than that minor complaint its really a fantastic game and I imagine it has the potential to be expanded in many ways (eg. enemies, special attacks etc). Keep up the great work!