First off, never use an installer. They're sketchy as hell, and they set off so many anti virus alerts. Instead, just zip up the folder, and distribute that. Next, I hated the lives system. The levels felt trolly, and that's okay. But not when you have only three attempts. The levels are actually really fun, but the lives system is not. Remove that, and this game would be legendary, but as it is, I'm not willing to go past the fourth level. I just didn't have enough lives to scope out new levels, and with each passing level it became more and more frustrating to get back to where you were.
I'm sorry to start off so negative, but on the brighter side, the game looks good, despite the minimalist graphics. There was some great ideas in there, and the game is not far from being really fun. I actually found the trolliness rather interesting, particularly on the first level where it seems that you need to fall then use your midair jump to pass, which was a neat consequence of the extra jump height. Great job for your first platformer, just please delete all code pertaining to the life system :P