03 September 2014

Improving the end-game of social strategy games

Improving the end-game of social strategy games

I removed Clash of Clans (CoC) from my iPad on August 20, 2014. The game had just reached two years old, and I had been playing it since February 2013. I played very actively (2-3 hours per day on average) until December 2013, then considerably slowed down (1 hour per week).

No new content

I think I slowed down, and eventually stopped playing mostly because no significantly new content was introduced. New content mattered a lot to me because I had reached Town Hall 10, the very end of the game, for many months. So far, the game has received four updates in 2014.

Month Description
January Introduced Hero abilities, which are not really a new gameplay feature, but rather a design fix to encourage players to use and upgrade their heroes. Great, and perhaps even necessary, but no impact on battle strategy or base design.
April Introduced Clan Wars, a feature asked by players since the game came out. My clan was very excited, but we stopped Clan Wars after a couple weeks. We realized that the match-making algorithm alternated pairing our clan against once a much stronger clan, once a moderately weaker clan. Clan Wars require a lot of time and in-game resources, so we kept asking for enemy clans, but only attacked when we were sure to win. After a few weeks, we realized the Clan Wars rewards were not worth the frustration, so we stopped match-making.
May Mostly usability tweaks.
July Improved Hero abilities. Once again, this was more a design fix to encourage the use and upgrading of Heroes than a new feature.

Moreover, in these four updates, the Hog Rider received three nerfs, but my base still got trampled by mass-hog armies. (Yes, anti-hog base designs exist, but these designs are very vulnerable to air attacks). The Valkyrie was buffed twice, but it still was not enough to make her useful for her cost. To sum up the last 8 months, no new mechanic, be it a unit or a tower, was introduced, and I did not find the balance tweaks adequate.

Lessons for social strategy games

Troop synergies

The game was released with 10 basic units that make sense when used together. For example, the Giants are slow and target defenses so that the Healer can follow them without being hit. These synergies are expected: the team had time to iterate and polish before launch. But introducing new troops after launch is tricky: the new troops must 1) have an interesting gameplay element, 2) complement existing troops, and 3) keep existing troops useful.

The Minion is a perfect example: it is cheap and flying. This makes it a great complement for farming with Barbarians and Archers (called the BAM strategy). It is also great for high-level PvP when paired with Balloons (Balloonion strategy). And since it costs dark elixir and has low HP, it can't be used by itself.

The pricey Golem is another great example: it synergizes well with Wizards and Pekkas (GoWiWi strategy), which are necessary troops in high-level PvP. The Golem's production stats are perfect: 45 minutes to make, and a cost of 2.5 hours-worth of dark elixir, which is the same as Pekka. The Golem was clearly designed to be trained in parallel of Pekka. Plus Supercell must have made a lot of money from players gemming it!

On the other hand, the moderately expensive wall-jumping Hog Rider does not complement any other troop. Neither does the Valkyrie. Interesting ideas, but no synergy! Supercell keeps trying to fix them, so they may have realized that. Or maybe Supercell abandoned them completely, and has been working on more troops, such as the Spider, Centaur, or Yeti, which have not been released yet, but were leaked in July 2014.

More things to do in the end game

As the Town Hall levels go by, so does the average duration of building upgrades. For example, upgrades take 3-10 hours at TH3, 1-3 days at TH6, and 7-14 days at TH10. By TH10, the player should have 5 Builders, so the average time between two building upgrades is still 2-3 days. During these 2-3 days, players come back to the game only because their troops are ready for battle, not because they have something to do with their base. But by TH10, players have spent months being progressively conditioned to come back for their troops and not their base. So they still come back, but more and more reluctantly, since the rewards are less and less frequent. At some point, they unlearn the habit of coming back to play: what's the point when nothing seems to be happening? They eventually stop playing.

Possible solutions involve shortening upgrade times or providing more builders, but both may seem like Supercell would lose money. The game should at least give players things to do with their buildings (beyond collecting resources twice a day). The Bomb very short upgrade times have been a step in that direction. A crafting system like in Monster Legacy, or Angry Birds Epic, but applied to strengthening buildings, or increasing towers' rate of fire, may increase the game's lifespan even more.

01 September 2014

List of tower defense games

I had started to compile a list of tower defense games a couple years ago, but never managed to finish it. The goals were to 1) list the basic gameplay elements that define the tower defense genre, 2) spot original gameplay elements that have made the genre progress, and 3) track the history of the genre, much like what has been done for shmups.

Name and URL Release date Image
Players Platform
Bosses Path
Backyard Monsters early 2011
single player + Facebook friends Flash on Facebook
Champion units never die Free path
Receive and donate monsters from/to your Facebook friends. Send your troops against the base of another player to steal their resources. Half-cloned by Clash of Clans in 2012. By Casual Collective (now Kixeye).
Bubble Tank Defense 2009
Single player Flash
Has bosses Free path
Mega towers are a combination of 4 adjacent normal towers. Tower upgrade is a tree: all towers start as basic towers, then they become zone, slow, specialize against ghost, etc.
Canyon Defense 2007
Single player Flash
no Fixed path
Unlock towers by completing missions such as building 15 towers or acquiring $1000. Developed by Russian studio Iriysoft.
CreepSmash 2008
2 to 4 players Java
no Fixed path
6 tower types, each with 4 upgrade levels. Player can specify AI for each tower (eg. target creeps with fewest HP). Receive income every 15 seconds. Increase income by 10% of the price of the creeps you send to your left neighbor. Receive creeps from your right neighbor. Green creeps regen life, white are immune to slow, blue are fast, red have lots of HP. Winning strategy: sell towers to send more creeps to increase your income faster than other players. Attack-defense gameplay. 4-player games, quickly turn into 2v2. Developed by a group of German students. The community is mostly German. open source.
Cursed Treasure May 2010
single player Flash
Has bosses fixed path
3 families of towers: Demon (fire AoE or burn DoT), Orc (poison DoT or strong single-target attack), and Undead (freeze, fear, or slow). Towers gain XP and level up by attacking creeps. Tower effects change when they level up. Creeps are assassins (hide temporarily), crusaders (block damage), monks (heal other creeps), and other medieval characters. Each level completed grants the player XP used to level up to acquire and level up passive skills such as more gold at the start of the level, more gold per creep, reduced tower costs, or increased tower range or damage. Player can use 3 active skills: cut tree to place tower, temporarily double the fire rate of all towers, and splash meteor damage in an area. Developed by Russian studio Iriysoft.
DemonRift TD Sep 2011
Single player Flash
2 Bosses Fixed Path
4 types of towers (swordsman, archer attacks long-range but not short-range, knight can chase fast enemies, and golem can stun and block up to 5 enemies). Command points are generated over time and when killing enemies, and are used to buy or upgrade units. Upgrades only add more creatures to a tower.
Desktop TD release?
Single player Flash
Has bosses Free Path
Creeps go from top to bottom or from left to right. Mazing/juggling matters a lot. By Casual Collective (now Kixeye). Spawn, flying, and many other kinds of creeps.
Dungeon Defenders 2011
single-player Unreal Engine
No bosses Fixed Path
3D. Originally a showcase of the Unreal Engine. Source code available.
Flash Element TD Feb 2007
Single-player Flash
Has boss? Fixed path
Start the first level with the 3 basic towers. Kill enemies to earn a bit of money to upgrade towers. At the end of each wave, earn 10% of your current money (+5% per skill point spent in a certain research skill). Earn Wood every 8-10 waves to unlock towers (earth, fire, water, and combo of the 3), skills, or increase your life. Also known as 3d tower defense.
Garden TD release?
Single player Flash
Has bosses Fixed Path
Spitting cactus are overpowered, gnomes are useless.
Hold the holy pig release?
Single player Flash
Has bosses Fixed Path
Towers are elemental: water slows down, earth is zone damage, fire attacks fast, plant poisons, wind only attacks flying creeps.
Mini tower defense release?
Single player Flash
No boss Fixed path
Creeps are tanks, towers are lasers. Winning a level gives points that can be spent to increase tower powers.
Orcs must die Oct 2011
Single player XBLA and Windows
No Bosses Path?
The game happens in 3d like a normal FPS. Creeps are Orcs. The player controls an FPS avatar with deadly skills and places traps and archers in that 3d-FPS view.
Plants versus Zombies May 2009
Single player Flash
One final boss No path
Zombies come from the right towards your house on the left. 5-6 lines, zombies never change line (except when you use garlic). Every 5 levels, there's a mini game. Plants are cards acquired when winning levels. No shortcuts, just clicks. The money is sun, it falls from the sky and players have to click on it to collect it. Click fest at higher levels. Five worlds: backyard by day and by night, pool by day and by night, roof by day. Lots of Easter Eggs. Very easy to understand and play through.
Rat Poker 1998
Single player Windows 95 and 98
No boss Fixed path
Tower defense where creeps keep looping until you order them in series like Poker hands. The player has to organize rats in series resembling Poker series (three of a kind, six of a kind, rainbow series, etc.). Rats are walking and can be grabbed and released at specific locations.
Turett Tyranny release?
Single player Flash
No boss Fixed path
Creeps HP keep increasing wave after wave. Kill creep to get money. Unlock, place, and upgrade towers with money. Towers have a size (e.g. 1x1 or 3x3) and can only be placed where they fit. Walls constrain towers' line of sight. There is friendly fire between towers, but you can pay to protect them from friendly fire.
Vector TD release?
Single player Flash
No boss Fixed path
Usual basic TD. Graphics resemble CreepSmash. Steep learning curve.
Viking TD Release?
Single player Flash
No boss Fixed Path
Creeps are boats of Vikings, towers are catapults and others. Towers are unlocked progressively in pseudo-quests such as "build 5 catapults to unlock the tree of wisdom" or "kill 3 Big Boats at once with a spell to get the Stone Head". By Russian studio Iriysoft.
VR defender Y3K April 2007
Single Player Flash
No boss Fixed path
6 kinds of towers, such as normal, slow, and flame thrower. Tower appearances reflects its upgrade level. It's hard to figure out which strategy to use as ennemies just only keep having more HP wave after wave, cf also player feedback. Graphics resemble CreepSmash.
Wicked Defense 2007
Single Player PC
Has bosses Fixed path
Some creeps can buff other creeps. Spells can slow down or damage monsters. Weird graphics. 3D.

And a list of games I have not broken down yet.

Name Comments
W3 mod
Colony Defense The terrain is a sphere, which gives a Populous-like view of the planet.
Sol Survivor 3D, fancy graphics, multiplayer co-op
Garden Defense
Defense Grid Matrix atmosphere, 3D, fancy-ish graphics, fixed path.
Fieldrunners Resembles Desktop TD, old-school war atmosphere, kawaii 2D god-view graphics.
TriDefense for iPhone
Besiegement for iPhone
The Horde 1994, contender for first TD game around; Its FAQ says that The Horde currently deletes all other non-horde saved games in NVRAM when you save a game
Harvest: Massive Encounter Creeps are aliens, towers are human. planet exploration atmosphere.
Protector Towers are medieval characters.
Immortal Defence
Pixel Junk Monsters
Lock's Quest DS game
Guns' n' Glory For iOS. UI is intuitive, but moving units around looks clumsy. Video.
TowerMadness iPad game, free placement, towers can be upgraded, creeps are aliens, lives are sheeps that you have to protect. 2 players can play at the same time on the same ipad, but there are no interactions between players (no co-op, no PVP).
Starship defense DSi game, slow, fixed path, rubbing/touching creeps with stilet inflicts damage. towers can be positioned on slots on the wall or on the roof. Video.
Castle-Combat Clone of Rampart, old game from 1990, possible origin of the TD genre.
Kajaani in space
Lockdown TD "lifting" system that lets you move towers temporarily and reposition them between waves
Pokemon TD So successful it has a sequel.
Ninja vs Pirates
Starland Multiplayer

And a list of lists of TD games, mostly Flash: