Pros:

-Great unique idea
-Excellently executed
-Building the barricades is great and fun

Cons:

-Incredibly hard without a friend or someone else to play with
-Small map
-Music gets annoying after awhile

Conclusion:

-As a mapper myself i have little to no idea as to how you accomplished this. Well Done
-I think you should take this idea and make many different small maps with the same barricades and stuff just differently placed giving a change of scenery but still the core idea of barricading and building a rocket