Bullbuster

Tetsuro Okino, 21 years old, just joined Habuto Kogyo, a company that uses giant robots to fight monsters. He has been fascinated by robots since he was a child and has followed their development, so the chance to become a robot pilot is like a dream come true for him. Okino goes to work with high expectations, but what awaits him is a company that's on the verge of collapse. The reality is that even firing a single missile is much more costly than he had imagined, and all the choices are at odds with each other!
(Source: Kadokawa, translated)