Fall of death
-You start at the top of a really really tall level with small bunches of ammo, and you fall.
-On some places are vanishing tiles, so that you may stop falling for a second.
-The level's horizontal size may change or the path may have curves (horizontally), but there should always be belt events on surface tiles, so that you can't just stand still, and these belts should be faster than running speed, so that you'll have to jump or else you'll start falling again. There may be wind events above the belts as well, so that jumping has no effect either.
-If there are any springs in the level, these should be made that way, that they'll flash (can be done by using MCE's and belts). This way it's never entirely sure that you can stay on one spring.
-There may be sucker tubes sending you up or down.
-There should be some secret places where you recieve powerups or carrots, like a tiny one tile wide passage on the edge of the level. I recommend not to use 'walled powerups' which you need to get with bouncers or electro blasters, as you must remember we are falling really fast.
-There may be some ceiling springs that will dramatically limit your control.
-Horizontal springs can be really useful to bounce players from one side of the level to the other, which will make it less likely they land on a surface, which would slow them down.
-Freeze pickups may be used to take people completely out of control (no shooting, no steering, no jumping, ...).
-Players can be 'trapped'. You can do this by making a sucker tube event that holds the player for a few seconds. Everyone passing by may be able to shoot the player and score a point.
-Players falling faster can be slowed down by adding destructable tiles or trigger crates. This way you can bring everyone together again.
-Levels should have all kinds of ammo. Faster falling players will need slow ammo like seekers or pepper spray to hit the others, slower falling players will need bouncers to shoot players that have fallen faster. Electro blasters are useful if you split up the level into two paths with a small wall in bedween. Freezers may be used to slow down players falling at the same speed as you do. RF can be very useful to bounce off walls or to go down faster (or slower (or even up) if you double jump) in narrow parts. Toasters can be very useful if you are one of the faster fallers as people above you will need to dodge your line of fire. TNT can be used to slow down people in narrow parts.

Level types
-Battle mode (Battle): the level should have warps back to higher parts of the level and should end in a line of warps (preferably with different IDs).
-LRS mode (Battle): The level starts in a circle sucker tube with a door that gets closed as soon as one gets 'sucked' through it (with a trigger crate). In front of the door, the sucker tube should wait a second to prevent multiple people from going through. The player that went through the door will be put in a small no fire zone-room with a trigger crate to open up the rooms floor and another door in the circle tube, so that people will get warped into the level all at once. The level should end in a fighting arena with ammo and one or two important powerups available (not all powerups, players should just make sure they don't run out of ammo if they have a powerup that is not in the fighting arena). The killed players should be put in a sucer tube, preferably near the fighting arena so they can see a part of it. Last player to survive wins the game.
-Treasure mode (Treasure): There should be diamonds in the level too. The level must end in a line of warps. Just above the line of warps, there should be a line of EOL events. First one to reach the bottom of the level with the required amount of diamonds wins.
-Team mode (CTF): The teams should start seperted. The blue team box has a door like in GroundForce levels to start the game. At the start, all blue players are being sucked to a Red base and vice versa. In the level, there should be several places (two or three) where a player can get the flag of the opposite team (they must be warped to the base and then warped back to where they came from, this can be done by using a trigger zone in front of the warp to the base that puts a solid block (a 'closed door') inside the sucker tube, so that the player will fall down. The block must then be removed with another trigger zone, and the player will be warped back to the correct place). It's important they will be sent to the enemy base, this can be done with a trigger zone just after the starting point. The bottom of the level should have a sucker tube that sends the players to their own bases. If a team scores (or if a team reaches the needed score) the level is over. If not, the players will start at the top of the level again.
-Race mode (Treasure): The players should start in a GroundForce-type box with a door so that one player may start the game by hitting a crate. The level should end in a line of EOL events with a lot of diamonds just above it. The first one to reach the bottom wins.
-Multi-lap race mode (Treasure): The players should start in a GroundForce-type box with a door so that one player may start the game by hitting a crate. The level should end in a warp line that sends the players into a tube that sets their personal lap count using trigger zones. Then, they should be warped back to the level. After the last lap has been finished, the tube should send the player to some diamonds and an EOL event. The first player to reach the needed lap count wins.

You may want to end a Race mode level with a podium for the fastest three players. The fourth should hit an EOL event in a room full of diamonds, under the winner's place. If there are less than four players the winner should be able to end the level too, preferably by shooting a (really really strong) destructable wall tile next to him with a trigger crate on top of it that opens the floor under the winner, so that he falls in the 'endroom' to end the level. It's fun to give the first player to finish one gem, the second two and the third three, so that the player list shows who won. This system is hard to explain here, just find an online race level with a podium and see how it's done.


Sources
-Inspired by Race 2.
-GroundForce concept by ET AKA Alien.
-Podium system I described is based on one I saw in some race levels, but I'm not sure who designed it first.
-Batteries in my keyboard are made by Top Craft, thank you for making batteries that contain enaugh energy to write all this.

RRowns.