Mega Man X5/Parts

By default, after beating one of the eight main bosses, you'll be given the options "Weapon + Life" and "Weapon + Energy". Pick one to get either a Life Up or an Energy Up. However, if the boss was on level 8 or higher, you instead get "Weapon + Life +" and "Weapon + Energy +" options. Then you get an additional Part along with the Life Up or Energy Up. The Part you get depends on which option you pick; this means you can't get all 16 Parts in one playthrough. The most Parts you can get is 8, and for that you'll have to waste time at the beginning. The bosses' levels rise as the countdown progresses, so you'll have to enter stages and deliberately lose all your lives, not fighting any bosses until the first boss's level reaches 8. That means you'll have to cut it close to stop the collision. Also, once you've earned a Part, you still won't actually get it until two stages later.