This game was great, but it had three main problems I would suggest fixing for the sequel;
1) An option to play the game in 2D, my laptop lagged a lot on most levels :(
2) Bonus levels, in hidden doorways, or as awards for unlocking a certain amount of gems/cages, so that it's more fun to go back and replay levels to find the bonus levels.
3) A tougher boss to challenge us ;)
Other than that great game though :) love it!
haaah got an awsome glitch! Get the Tack Shooter, keep pressing tab untill it gets to "Faster Shooting" and keep pressing enter untill it says hypersonic speed. Stuffs up ur money tho. Repeat this meseage to kep the information alive