I'm taking that as:

Get core requirements done quickly. Hypothetical example:

• Player can move
• Player can shoot
• Enemies can be hit/killed
• Level win/lose conditions in place

And once that's out of the way, you have the rest of the time to improve everything else about those things:

• Player can move, is animated, feels great, momentum causes delay animation when switching movement directions
• Player can shoot, with cool muzzle flash, hit effects, kick-back, camera shake, implement an ammo counter and reload system
• Enemies can be hit/killed, but have a shield so they can't be hit from the front, and have sound effects and animations
• Level win/lose conditions in place, with added fan-fare like celebratory particles and sounds and a reward or xp system.