The observation that I have made after playing hundreds of rounds of Netkeen is that a player in pursuit of his opponent is putting himself in a bad position. First of all, the player being chased around the map will get to the power-ups first. Secondly, and more importantly, the munitions in this game usually travel too slowly, and too horizontally, such that the player being chased always has ample time to move out of danger.
Given the physics of Keen, if a player elects not to fight, he can usually avoid combat if the map is any more complex than a single, level platform. If one player is a tryhard, and the other is a novice, the game usually plays out with the experienced player running away until his opponent puts himself in a poor position.
So, when I make my levels, I accept that players will always be able to run away; however, I try to design the map so that the pursuer can counteract any such attempts to avoid combat. If there is an escape route, then there should be a counter-escape route less than a screen-width away. In other words, there should always be a way to trap a player. The game then becomes a battle of attrition, where the goal is to control the map and therefore, acquire more powerups than the adversary. Most of the powerups, especially vitalins, are stored in the middle of the map. Once you have a 2:1 advantage in health, you can then attempt to flush the opponent out.
The following screenshot shows my favorite part out of all the Netkeen levels:
In this corner of Sandwept, from the Keen 4 level pack, Keen has the potential to trap Lindsey. For the purposes of a duel map (which this map really isn't), I would remove all of the power ups in the corner and place more bombs atop the platform upon which keen is standing.
Another good element to include in duel maps is an exposed pole. Poles allow for vertical mobility to other parts of the map, but they slow a fleeing player down AND leave him totally exposed (especially to bombs). Similarly, consider using sprite platforms instead of jump through ledges so that shots are not stopped.
High Noon (http://puu.sh/2oG9v) is probably my favourite duel level of all, and it makes use of a pole on either side of the map. The level is open enough so that there is room to attack and dodge, yet it still a possesses distinct figure-eight structure. There are distinct "strong positions" atop the blue platforms, which feature a bomb spawn and nearby powerups, and a semi-strong position at the bottom in the middle which is shielded in all directions from stunner shots, but open to bomb attacks from the poles. The weak points are the bottom corners of the map. The pole gives a fleeing player an escape route, but the placement of the green platforms allows the pursuer to pogo atop the blue platform. Clearly, then, the strategy is to get a bomb early, and try to pin your opponent in the corner.
The biggest complaint I have about this level is the single, green platform in the very centre of the level, which makes it difficult to engage the opponent from across the blue platforms, for it impedes shots taken from a standing position. I would replace it with a stationary platform sprite. Alternatively,keep the green platform there, but put small poles mounted atop the center of either blue platform so that a player could quickly press up and take a shot across the map from a slightly elevated position.
In summary, here are a few points about dueling level creation that I think people should keep in mind:
- The level shouldn't be too big. A 50x50 combat area is probably the biggest acceptable size for a duel map.
- Don't put in too many hazards, and when you do include them, do so with purpose. In a normal keen game, hazards are necessary to provide a challenge to the player and to make the game fun. In a duel (not a points race duel, either), they are present to augment the duel in some fashion (e.g., slowing down a player, providing a reward for risk), but not just to make the level more difficult for everybody. Adding hazards for hazards' sake generally makes the game more irritating for everyone.
- Guns and bombs should be plentiful, but not overly abundant.
- Levels need not be totally symmetrical
- Try to build a level that rewards aggression (e.g., good powerups in an exposed middle area).
- Put strong points with ample powerups next to weak points with few or no powerups. Chasing an enemy is usually a losing tactic, but if you have him pinned and you can max out your health, it is then to your advantage to press the issue.
Here is my latest level, inspired by the structure of the polycyclic aromatic compound, pyrene (http://puu.sh/2oJTS). Here are some key points about the level:
- It is not mirror symmetrical (although it is sort of rotationally symmetrical, not that this matters too much), but the power ups are fairly distributed based upon the starting locations of the players.
- There is plenty of ammunition.
- It is more like a Biomenace level than a Keen level, in that there are long, horizontal platforms so that shots have space to travel. This level has four "floors," so to speak. The slopes give some cover from shots, but bombs can flush players out from cover.
- The top of the leftmost cyan ring and the bottom of the right most cyan ring are the weak points. They are located right next to strong points (40HP, gun, bombs).
- The leftmost pole makes the bottom blue ring a stronger position than it would be otherwise, as it provides a safe, albeit slow, escape route to the left.
- The rightmost pole and the jump through ledge strengthen the two strong points, should the opponent be trapped in the respective weak point. The pole allows the aggressor to peek from the top of the bottom right cyan ring and throw bombs without losing his position, whereas the the ledge provides the aggressor with cover from above should his opponent attempt to break out to the right.\