The Levelmaker's Guide to the Galaxy
This is an adaption of a community-driven discussion to compile random tips and advice for improving level design. It is ever-expanding, so add as you see fit and come back every now and then to see what's new! Feel free to also add onto existing tips with your own thoughts in italics.
Game mode design
• In Rabbit, avoid adding teleporters. A rabbit able to escape easily through conveniently-placed teleporters is a surefire way to annoy the rest of the server. If you must add teleporters, at least orient their outputs away from other teleporters, or perhaps add spawn points near a particularly tempting teleporter to so a player may spawn and potentially disrupt the path of a fleeing rabbit. The idea is to discourage rapid escapes, which require virtually no skill and impact a chasing player's ability to catch up. In the absence of quick getaways, players must rely on their raw skill to survive, which promotes competitive gameplay.
• In Retrieve, keep the flag count low (3 or maybe 4 max), and even lower if there are more than 2 teams. Levels with too many flags will be difficult to cap and will likely result in a neverending back and forth exchange, as players steal and recapture flags repeatedly.
• In Zone Control, take care when adding more than one flag. The reasoning is similar to the above, if both teams have at least one flag, then the ensuing result will likely be a back and forth exchange of stealing and recapturing zones. This can be worked around with some thought. Try adding turrets and aid kits as well as obstacles to slow down a player entering a zone area. The idea is to encourage combat, potentially allowing one team to obtain both flags, which would address the stalemate concern.
• In Soccer, design fairly-easy-to-score goals. Nobody enjoys a stalemate Soccer game. Be very intentional with your placement of barriers, and consider how their placement and angles will affect the Soccer ball.
• Straight edges can sometimes be an eyesore. Experiment by rotating, shrinking, and expanding walls, as well as designing asymmetrical passageways or adding rounded corners. Oftentimes a fluid level is more visually pleasing and entertaining to play than one with lots of 90º angles.
• Place turrets in a base but not directly smothering the flag. A good placement would require the enemy to pass by a turret on their way to the flag, ensuring they're vulnerable both in travel to the flag and away from the flag, instead of just for the brief second they're stealing the flag.
Internal base turrets which guard the flag may enjoy the most contact with an enemy, but are also likely the primary targets of enemy flag rushers. External base turrets, placed in seemingly unhelpful locations, might avoid an enemy's phasers and still deal damage to an enemy should their path stray in the heat of the battle.
• Place turrets at different angles on walls. Turrets with different field and angle of view may defend better against enemy rushes. However, take care to now allow the turret to be easily shot by a player creeping around a corner. Remember that turrets can only sense enemies in a 180º radius, and so a player firing at the turret from an obtuse angle will be able to destroy it without any contact.
• Limit the number of turrets in and around each base. For a small level, 2-3 turrets is a good number. For a medium-sized level, 4-5 turrets is sufficient. You will rarely create levels large enough to warrant more than 5 turrets. These figures do not include neutral turrets, which can be added elsewhere throughout the level, but level designers should not go crazy on the neutral turrets, either!
• Bonus engineer tip: Place a turret on a wall inside a bottleneck. Enemy players cannot bypass the bottleneck without destroying the turret, so it acts like a laserbeam that blocks travel, but can also fire back!
• Appreciate empty space. Don't overwhelm your level by adding something everywhere. Empty space will be naturally filled in-game from players moving, hiding, strafing, chasing, exploding, etc. After you've completed your level, take a second look and try to remove 3 items. Remove "fluff" - any items that aren't crucial to the design of the level.
• Avoid cramping hallways and bases. Areas too small might encourage intrusive habits such as camping and clogging.
• If your level features bases, avoid placing team spawns near points of interest (eg. CTF flag spawns, HTF/RET flag goals). This can lead to a defender respawning immediately after being killed by an attacker, with the addition of replenished health and energy, giving the defender an unfair advantage.