The hurdles
There are normally 6 plates per 100 meters scattered across the track in every heat, but the host can pick 4, 6, 8, 10 in the race settings. The plates are drawn evenly from Fingerspurt's 19 hurdle types, one round per 100 meters, and sit in one of 3 lanes, and you have to steer for them: only whoever passes within 1 meters sideways picks the plate up. Some help the collector, some hit the whole field, and some send a hazard onto the track that everyone else has to dodge.
Some of the hurdles are unfair on purpose: that is the point, when everyone can see what hit them and laughs about it.
Shuffle
Effect on the collectorThe plate keeps changing its look and shows a new hurdle every 1.2 seconds, and a flashing frame gives it away. You get the hurdle the plate shows the moment you touch it. Wall and the hurdle types that already sit on the track are not in the mix.
Big
Effect on the collectorMakes the runner noticeably bigger and quite a bit faster for 6 seconds.
Small
Effect on the collectorMakes the runner noticeably smaller and quite a bit slower for the same 6 seconds, the mirror image of the big plate.
Boulder
Hazard on the trackA giant boulder appears 10 meters behind the last runner, in the leader's lane, and rolls forward at a pace only the fastest tappers can stay ahead of. It knocks over everyone it rolls into, so steering aside in time is the whole game.
Reverse
Hits the fieldFlips the finish line and the direction of travel for everyone still on the track for the rest of the heat: suddenly the start line is the finish. The plate only sits between 50 and 85 meters on a 100 meter race (further out on 200 and 400), so the flip always lands late in the race.
Skateboard
Effect on the collectorPuts the runner on a skateboard with its own speed for 3 seconds. With Motion turned on, you steer the board by tilting the phone.
Airmail
Hazard on the trackPicks the runner in front, the collector included if she leads. Everyone sees a shadow following the chosen runner, and after 3 seconds something drops from the sky: an elephant, a grand piano or an American football, with equal odds. The elephant and the piano eliminate the chosen runner and anyone standing too close, and stay on the track for the rest of the heat; the only way out for the chosen runner is a well timed jump or a twirl with a full meter. The football bonks the chosen runner on the head and flies off the track, and the runner wobbles on.
Race Walk
Hits the fieldSlows the whole field down a little, and everyone waddles in a race walk for 10 seconds. If you are on a skateboard, it disappears.
Teleport
Swaps two runnersSwaps position, lane and speed between the collector and a random other runner on the track, 1.5 seconds after the plate is taken. The collector is gambling: draw the last place runner and you give away the lead, draw the leader and you just stole the race.
Wall
Hazard on the trackLooks like a totally different plate, but actually raises a wall right where the plate stood. Hit it with your feet on the ground and you get thrown straight backwards onto your back and stay there until the next tap. A jump or a twirl clears the wall, otherwise you have to go around.
Bubbles
Hits the fieldTraps half the field in a floating soap bubble, and the collector can get trapped too. A secret number of taps pops the bubble again, or it pops on its own after a while.
Roadworks
Hits the fieldNarrows the track itself for the rest of the heat for everyone still running. Only the room to steer in shrinks, speed is untouched, but the edge gets a lot closer.
Flipper
Hazard on the trackRaises three standing bumpers scattered across the track. Hit one and your speed gets mirrored like a pinball machine, and you can get bounced between several bumpers in a row.
Table Tennis
Effect on the collectorGives the collector a table tennis paddle for 5 seconds. The paddle swings on its own and knocks down runners who get too close in front of you. The holder runs faster from behind and slower in the lead.
Banana Peel
Hazard on the trackDrops between 3 and 5 banana peels from the sky, right in front of the leading runners in their own lanes, where they stay until someone slips on one. Hit one and you slip, but a jump or a twirl carries you right over it.
Lasso
Effect on the collectorHands the collector a lasso for 10 seconds. Touch an opponent with it and their feet are tied together. The holder runs faster from behind and slower in the lead.
Dynamite
Hits the fieldThe collector gets a stick of dynamite with a hidden fuse of between 4 and 9 seconds. Throw it on to another runner before it goes off: it blows up on whoever is holding it, and they stand there helpless for a moment while everyone else runs off. The stick also goes off just before the finish line.
Missiles
Effect on the collectorHands the collector a tomato, a water balloon or a newspaper for up to 10 seconds, and everyone else is told who is holding it. Swiping up throws it at the nearest runner ahead, who trips, drops to one knee or ends up on their belly until they tap themselves back up. The holder runs a little slower while holding the item.
The button
Hits the fieldThe collector gets a box with a button that can be held for up to 10 seconds, while they run at ×0.9 speed. A swipe down presses the button, and a force field sweeps out from them across the track at 35 meters per second. It hits each of the other runners once with a random effect for 2 seconds: a gravity field, a freeze or a stretch of spacetime. If there is nobody else to hit, it hits the presser.