You are on a roll. Goal or no goal. Its not important. Not now. A corner coming up out of no where and you respond. Shift posture, shift weight point, shift gears, shift focus. In a heartbeat. Instinctively. Ritualistic and primitive behavior overrides your rationality. Your fear. Yourself. If so only for a second, for a short moment, your self perception as person and as a human is removed. You're more than human. You're something bigger and far greater. You're a reaction. A reaction to external and direct stimuli. Your muscles, balance, heartbeat and breathing merge in perfect synergy. Your Reptilian brain runs the show now. Your reflexes and actions has reverted back to their successful prime states. You've gotten a special sense of time and space. You're ready for anything. Obstacles becomes opportunities. Borders becomes springboards. Dead ends becomes u-turns. In this mode nothing is impossible. Responding to stimuli and challenges your body is just a vessel carrying out commands of a primeval state of mind. You leap across a chasm. The old Limbic system in your brain tells you what the movement will feel like before you experience the sensation. You can take comfort in this, even in this unpredictable environment and snap judgment mindset there is a system capable of predicting at least what your movements will feel like before you commit to them. It is exhilarating and addictive. Fun and rewarding. You never want it to end. Not now. Not ever. Abruptly it does. Either by forces of physics or by human error. In a crude jerk your out of it, the reptilian brain that hijacked you is bluntly shut down and your back to your old self. You've lost your momentum.
Immediately, you want to get back into it. And all it takes is a leap of faith.
Mirrors Edge - An immersive FPP (first person platformer) that's all about momentum as you run around rooftops as a pacifistic Parkour messenger. The gameplay is very fresh and appealing, just as the visual style. It is beneficial for you to avoid enemies and to avoid engage in battles, if anything you should just disarm them and move on. And that's the key. Moving. Running along the side of a building, leap out towards an opposite wall at the very last moment, quickly bounce off that wall to reach a ledge above, pull yourself up, speed up and slide under some pipes, jump.... The level designs are a bit linear and the unavoidable halts, when you loose your momentum, and have to deal with enemies can be a bit frustrating. But the Free running gameplay and on-the-fly exploration makes Mirrors Edge a great playground game. Dice has a fantastic IP to build on here. In the next installments they can add to skill upgrades, a trick system, a multiplayer online component with co-op gameplay where you can string moves together with other players and Parkour parks etc.
Jet Set Radio Future - The Xbox sequel to the cultclassic Dreamcast game, just as bold and stylistic as its predecessor. You're still an inline skater, riding around urban city Japan and leaving a trail of graffiti behind you. Smilebit streamlined the gameplay this time around, simplifying the tagging mechanic and concentrated more on the Inline skating. The level designs were bigger, more areas to reach and explore. As you got increasingly better at the controls and learned to read the environment, you could ride (what almost felt like) forever. Especially in the free tag mode where the entire level was opened up for you. The skating is extremely satisfying and addictive. Smilebit is not around anymore but Sega still holds the right to the IP so who knows? Maybe we'll see a Jet Set Radio 3 one day? On the Wii, with Wiimote graffiti gameplay and balance board skating?
Building on momentum, whether that is used as a parry/grab move in a fighting game, as a back draft/speed boost in a racing game or as a trick combo to reach new areas in a playground game, can be a very successful and addictive gameplay formula. Its about flow and to maintain it. The idea is almost so simple its silly. Like throwing flat rocks and watch them skip across the water. Simple and fun.