Pros:

Good Ideas

Shots are cool and useful (base defense)

Good functional level design

Good action and pace with breaks in waves

Cons:

Bots are useless (base defense they walk in front of supply truck shoot it, and then the rest of the bots jump into fire and die)

Bots in Sandbox always walk in front of turret, die, and the rest follow.

Sandbox- laying down structures is buggy and doesn't always work right.

Good luck getting past 2mins in Sandbox

Conclusion:

Great ideas and good job on getting everything working. Just needs some polishing to be a great download.