Not bad for a first game. Objectives and controls are clearly presented to the player, and I'm into the kind of retro style of graphics. Mechanics and level changes work well, and overall presents a pretty good game play experience. Difficulty level tends more towards the less challenging side, although it does seem the challenge increases with subsequent levels, which is a nice touch. It would be nice if character movement was a little faster, though. After a while the character speed begins to feel annoyingly sluggish, and prevents a sense of urgency for the player. It would be more in keeping with the premise of the game if the player moved more quickly, and would create more tension for the player. This contributes to a more absorbing (and entertaining) game play experience.
Some things were less clear; were the green boxes an item the player can collect? If not, why are they included? What about the whole loaves of bread that appear to be out of reach, as they also are presented as collectible (though I could find no way to reach them). If they're just background details, they should probably not be animated or be placed so prominently. If they're collectible, it should be explained to the player in the same way the other elements are. I don't know if the player is supposed to be able to wall jump, as I could stick to walls but not jump or climb from that position.
I liked and understood the message at the gameover screen, but its almost illegible due to the layout. The font is difficult to read, and kerning contributes to the issue (letters are too far apart, creating less definition between words). That could use a rethink in terms of design and presentation, as it's important to the core concept and message of your game. You want to ensure that it's both clearly presented and easy to read, otherwise people will just ignore it.
Is it possible to succeed in the area where the tanks shoot dynamite? When getting hit in this area, the 'game over' is triggered from one hit, but everywhere else in the game a hit takes you back to the beginning of the area. I've played three times, but having to replay an entire game just to retry one area is annoying, so I won't be giving it a fourth attempt. Because I didn't get past this section, I don't know if there's a point to collecting the breadcrumbs. I hope there is, and that it would be made clear upon successful completion of the game (assuming this isn't a mini version of the Kobayashi Maru). Strategic save-points before difficult sections of the game allow the player to retry challenging parts without forcing a replay of the entire game, and therefor help the player stay interested longer. If the fact that success is not possible is the point of the game, you'll need to be a little more explicit in indicating that to the player at the end of the game.
Overall, not a bad game with some potential for improvement. Nice job.