System design case study / F2P support economy

Designing a companion economy

A system design case study for a companion feature that added AFK utility, care, social support, and long-term monetization depth to a live F2P game in Japan.

17 pet archetypes 4 AFK modes 60 progression levels 5 evolution gates

Challenge A quest- and task-heavy game needed an AFK layer for advanced players. Design response Pets became IP-connected helpers players could level, care for, and send to work across solo and team loops. Evidence The system created player affection, repeat reward value, and long-term monetization surfaces.

HD parrot pet artwork from the pet system

01 / Problem

A quest- and task-heavy game needed an AFK layer for advanced players

The daily loop was already full: walking, cooking, quests, teams, seasonal goals. Pets had to add progression and monetization depth while giving advanced players relief from constant tapping.

Player pressure

Active play was meaningful, but the daily loop needed a relief valve.

The game could not simply add another active feature. The better opportunity was to let players invest in helpers that could keep supporting their goals when they were not actively managing every loop.

Design criteria

The system needed to support solo progress, team goals, collection, and monetization at the same time.

Fit a care-based, IP-friendly game feature for the Japan audience.
Reduce active grind without removing the value of active play.
Connect pets to core loops.
Create new value and monetization potential through Pet Food, Soap, Super Soap, and pets themselves.

02 / Design response

Helpers woven into the Moominvalley story

Pets were written into the IP and its feel-good mood: the player cares for them, and the pets help the player back. Each pet runs one of four AFK jobs tied to a core gameplay loop, then banks rewards the player claims on return.

Step 01Assign pets to a job

Step 02Run 10-minute actions

Step 03Bank rewards offline

Step 04Claim them on return

10mOne AFK action cycle

144Maximum stored action cycles

24hMaximum offline accumulation

4Active pet slots at once

Design intent

The bag caps and split collection rates were deliberate friction, sized so pets supported the core game without replacing it, while pulling on three player habits.

Claim often

Output stopped accruing once a bag filled, so rewards waited until the player returned, turning claiming into a frequent habit.

Level up pets

Bag caps and base stats both rose with level, so spending Pet Food unlocked bigger stores and higher output at once.

Run every element

Rates were split across the four roles, so a full team of specialised pets out-earned a single maxed favourite.

Under the hood

Beneath the simple “send a pet to work” action, a hidden formula turned species, level, and evolution into the actual output. This was the balancing layer behind every reward, restriction, and monetization surface that follows.

Skill stat skill = species multiplier x level base stat x evolution bonus

Gold output gold per action = (2 x Gold skill) / 100

Ticket output tickets per action = (0.04 x Tickets skill) / 100

Treasure output treasure chance = (Treasure skill x rarity factor) / 100

Ingredient output ingredient chance = (Ingredients skill x rarity factor) / 100

03 / Role data

Pet roles and action profiles

Four collection skills mapped directly to four AFK outputs, making the pet collection itself a toolbox. Multiple pets stayed useful because different loops needed different helpers.

effective output = collection skill multiplier × level base stat × evolution bonus

Treasure

Valuable finds and task progress

Ingredients

Cooking and recipe progress

Gold

Soft-currency support

Tickets

Progression and utility support

Archetype multipliers

Each pet had a different skill profile

These multipliers were applied on top of the level base stat, creating meaningful differences between pets.

Pet	Ingredients	Gold	Tickets	Treasure
Bat	1.2	0.8	0.6	0.4
Cat	0.6	0.8	0.2	0.4
Owl	1.0	0.6	0.8	1.6
Squirrel	1.2	0.4	0.8	0.6
Parrot	1.2	1.6	0.6	0.6
Crawly	0.8	1.2	1.8	1.2
Dragon	0.8	1.2	0.6	0.4
Mouse	0.8	0.4	0.6	0.2
Creep	1.2	1.2	0.8	1.8
Frog	0.6	1.2	1.6	0.6
Hedgehog	0.2	0.8	0.4	0.6
Sakura Dragon	1.2	1.8	0.8	1.2
Air Dragon	0.8	1.4	1.6	1.2
Dog	1.0	0.8	1.6	0.6
Rabbit	1.6	1.0	0.8	1.0
Fluffycat	0.8	1.6	0.8	2.0
Hattifattener	0.8	1.6	0.8	2.0

Worked example / Parrot at level 60

One pet, four economic outputs

Run the Parrot's row above through the formulas with the level-60 base stat of 1,082 and no evolution bonus. The same pet reads very differently depending on the job it is sent to.

Gold per action · 3,116 coin bag cap

34.6

Ingredients common roll / action · 25 item bag

65%

Treasure common roll / action

32%

Tickets per action · 62 ticket bag cap

0.26

04 / Progression economy

Pet Food carried the long-tail sink

The system used a 60-level food curve, storage caps, and duplicate evolution gates. The important design choice was that late-game investment grew sharply while early levels stayed approachable.

1.30mNormal Pet Food on one straight level 1-60 path

2.46mTotal Pet Food when the duplicate merge tree is included

32Base pets represented by the final companion

1,082Level-60 base stat before species multipliers

Pet Food required by level band

Food costs stayed light early, then became the main long-tail sink after level 40.

Levels 1-10

2,462 Levels 11-20

5,373 Levels 21-30

39,600 Levels 31-40

108,000 Levels 41-50

407,200 Levels 51-60

737,000

Base stat growth

The same base curve powered all four skills before pet-specific multipliers were applied.

Lv 1

100 Lv 10

120 Lv 20

186 Lv 30

288 Lv 40

448 Lv 50

696 Lv 60

1,082

Full level curve

Level-by-level Pet Food, base stat, and storage caps

Toggle all 60 levels

Level	Pet Food to Next	Total Food Spent	Base Stat	Item Bag	Ticket Bag	Coin Bag
1	54	0	100	5	6	288
2	165	54	102	5	6	294
3	165	219	104	5	6	300
4	213	384	106	5	6	305
5	267	597	108	5	6	311
6	319	864	110	5	6	317
7	373	1,183	113	5	7	325
8	426	1,556	115	5	7	331
9	480	1,982	117	5	7	337
10	Evolution gate	2,462	120	5	7	346
11	480	2,462	155	7	9	446
12	480	2,942	158	7	9	455
13	542	3,422	162	7	9	467
14	542	3,964	165	7	10	475
15	582	4,506	168	7	10	484
16	624	5,088	172	7	10	495
17	666	5,712	175	7	10	504
18	708	6,378	178	7	10	513
19	749	7,086	182	7	10	524
20	Evolution gate	7,835	186	7	11	536
21	3,800	7,835	241	7	14	694
22	3,800	11,635	246	10	14	708
23	4,000	15,435	251	10	14	723
24	4,200	19,435	256	10	15	737
25	4,400	23,635	261	10	15	752
26	4,600	28,035	266	10	15	766
27	4,800	32,635	272	10	16	783
28	4,900	37,435	277	10	16	798
29	5,100	42,335	283	10	16	815
30	Evolution gate	47,435	288	10	17	829
31	10,500	47,435	375	15	22	1,080
32	10,500	57,935	383	15	22	1,103
33	10,900	68,435	390	15	22	1,123
34	11,500	79,335	398	15	23	1,146
35	11,900	90,835	406	15	23	1,169
36	12,500	102,735	414	15	24	1,192
37	12,900	115,235	422	15	24	1,215
38	13,400	128,135	431	15	25	1,241
39	13,900	141,535	439	15	25	1,264
40	Evolution gate	155,435	448	15	26	1,290
41	14,500	155,435	583	20	34	1,679
42	44,000	169,935	594	20	34	1,711
43	45,000	213,935	606	20	35	1,745
44	47,000	258,935	618	20	36	1,780
45	48,000	305,935	631	20	36	1,817
46	50,000	353,935	643	20	37	1,852
47	51,500	403,935	656	20	38	1,889
48	52,900	455,435	669	20	39	1,927
49	54,300	508,335	683	20	39	1,967
50	Evolution gate	562,635	696	20	40	2,004
51	74,000	562,635	905	25	52	2,606
52	75,000	636,635	923	25	53	2,658
53	77,000	711,635	942	25	54	2,713
54	78,000	788,635	961	25	55	2,768
55	80,000	866,635	980	25	56	2,822
56	81,500	946,635	999	25	58	2,877
57	82,900	1,028,135	1,019	25	59	2,935
58	94,300	1,111,035	1,040	25	60	2,995
59	94,300	1,205,335	1,061	25	61	3,056
60	Max	1,299,635	1,082	25	62	3,116

7,835Pet Food across levels 1-20 kept early progress approachable.

147,600Pet Food across levels 21-40 introduced real investment pressure.

1.14mPet Food across levels 41-60 made late-game growth the main sink.

05 / Evolution logic

Acquiring multiple same type of pets was meaningful

At each gate, two same-species, same-level pets merged into one stronger pet, so duplicates from pulls, offers, and rewards stayed valuable instead of disappointing. A final pet folded in 32 earlier ones.

2:1Same species and same level required at every gate.

32Base pets represented by one naturally built final pet.

31Duplicate pets consumed through the merge tree.

61hTimer sum across the five milestone gates on one straight path.

Evolution gates by level

Each node is the evolution level. Its timer is the wait to evolve the merged pet; rubies optionally skip the wait.

10

1 hour5 rubies to skip

20

4 hours10 rubies to skip

30

8 hours15 rubies to skip

40

16 hours20 rubies to skip

50

32 hours25 rubies to skip

50%chance of a bonus

Evolution roll

Each evolution ran a luck-based roll for a permanent bonus. A success added +10% to one AFK role; the other 50% gave nothing, creating small variation between two otherwise identical pets.

Treasure bonus12.5%

Ingredient bonus12.5%

Coin bonus12.5%

Ticket bonus12.5%

06 / Care modifier

Taking care of your pet was beneficial

Care was not only presentation. Mood changed AFK efficiency, while walking, leveling, Soap, and Super Soap turned care into a repeatable resource loop with real output value.

Mood multiplier

Mood gave the care fantasy a real system effect. Each mood band was an efficiency multiplier on every AFK output, so a sad pet at 0.6× produced less and a thrilled pet at 1.5× produced more. Better mood, better results.

0.6×Mood 0-500

1.0×Mood 501-1,000

1.2×Mood 1,001-2,000

1.5×Mood above 2,000

Walking

Real walking restored mood for every active pet, connecting the companion fantasy back to the core walking loop.

Grooming and Soap

Standard Soap added +600 mood through a small interaction, turning care into a repeatable resource action.

Super Soap

Super Soap added +600 Super Mood and enabled Super Mode: enhanced ingredient finds and a chance to attract another pet.

07 / Reward economy

The pet system created reusable reward surfaces

The system created a compact family of rewards that could be reused across free progression, premium tracks, login rewards, team rewards, events, loot boxes, store offers, and personal offers.

Pet Food

Raised level and long-term output power.

Pets

Created collection, role choice, and duplicate value.

Soap

Restored mood through grooming and repeat care.

Super Soap

Unlocked temporary high-value Super Mode effects.

08 / Design reflection

What worked, where pressure built, and what I would revisit

System strengths

Successful monetization addition generating roughly 10-15% of total revenue and opening many new reward incentives
Gave active players a new progression tool to upgrade and use
Tied into season and team progression, supporting both solo and competitive play
Long-term value for basic, premium, and duplicate pets
Super Mode created temporary jackpot potential

Balance pressure

Steep level 41-60 food wall
50% no-bonus evolution result
Pet Food supply needs careful event and offer pacing

What I would revisit

I would make player-facing stat effects clearer, soften or better explain the 50% no-bonus evolution result, and smooth the late-game food wall without removing the long-tail sink.

Outcome

A collection system where every pet was both a character and an economic decision.

The design linked identity, care, AFK output, duplicate value, progression math, and reusable reward resources into one long-term companion economy.

Game design Systems design Economy balancing Progression design