Samus uses a multi-breast upgrade.

A smile crossed Samus's lips as a devious thought ran through her head, hearkening back to her mental comment about porn stars. If she wanted more boob, but didn't want them to get too big, why not literally have more boobs?

"Computer, are there any upgrades to give me additional breasts?" Her hand ventured toward her pussy as she thought about the possibility. She would look like a freak, and that image excited her.

"Yes, Samus. There is the multi-breast upgrade, designed to add a configurable amount of breasts to your body."

"And would it be compatible with the Energy Tank Implants?" Samus massaged her clit through her suit. The day was just getting better and better.

"Of course."

"Perfect!" Samus almost skipped over to the console, she was so eager. She brought up the upgrade on the monitor. Before confirming her selection, it asked how many new boobs she wanted. "Let's just go with two for now, I can always get more later." Samus made her choice and finalized her selection. Like last time, a receptacle opened, containing the chip within. Samus quickly grabbed it and plugged it into her suit.

Immediately, she felt an itchy tingling below her existing breasts. She brought her hands to the affected areas, and could feel two new nipples placed below her first pair. Then she felt then push up against her fingers as the flesh under them swelled out, growing into a new pair of breasts just as large as her original, natural pair.

The implant upgrade on her suit then emitted a noise. "New breasts detected. Administering implants." She felt the familiar sensation as the gelatinous material was injected into her new pair of tits, pushing up her initial pair until she had cantaloupes resting under her basketballs.

"We're not done yet!" she said with an excited smile. She strutted back to the energy dispenser. As she made each step, her four round orbs bounced and jostled, causing her to stumble and nearly lose her balance. "Looks like I'll need some time to get used to these," she admitted, giving her new pair a slight squeeze, cooing at the sensation. "Or I get some ass implants to balance me out..." She filed that thought away for later.

Back at the dispenser, she took no time to insert her arm, practically drooling in anticipation of what was coming. She cried out as she felt the energy fill her new tits, "Oh yes, this is it!" They surged bigger, fuller, pushing up the upper pair even more. Samus thrust her free fingers into her waiting pussy, helping herself reach climax. She came again and again. "Bigger! Make me bigger!"

But it wasn't long until they, too were at max capacity. Completely filled up, Samus now had four giant titties attached to her chest, as perfectly fake and round as could be. Her suit barely covered her nipples, with nearly half of her stretched areola at full display. She freed them from the confines of her suit, watching them wobble like four balloons. She giggled and moaned as she played with them. She was in titty heaven.

"Maybe I don't need to be a bounty hunter, anymore," she idly thought to herself. "I've saved the galaxy plenty of times. Maybe I retire and let someone else have their time to shine."

She looked back over to the monitor. A myriad of options awaited her. More breasts. More implants. Something completely different. Or she could see what else the research facility had on offer, find something fun to do with her new boobs.