Beautiful. Charming intro with a great transition. I appreciated the concept how you had to manage what you were carrying to see which gun you can shoot. Added a lot of depth to the strategy.
My only suggestion for improvement is the control scheme. I instinctively used the arrow keys, which only work sideways and my brain did not want to compute the space bar as a means to reach the higher level and 's' to get back down again ^^
Cosmetics on an otherwise stellar entry! Really good job, you guys more than deserve a beer now!