Scratch

I recently made a bomberman game for my school project, I made sprites for the blocks that can be blown up and sprites for blocks that cannot be blown up (like any traditional bomberman game)

the problem i am experiencing is that my dude that i navigate is able to walk through all the blocks, and that can't do, because it defeats the purpose of the game; to give you an idea of what i mean, i uploaded the game for you guys to see:

http://scratch.mit.edu/projects/s2o7/1095714

that's the main problem, i don't know how to set the code so that bomberman cannot walk through blocks.

Any feedback/advice would be really helpful thank you