World Explorer: the play log

The game keeps a log of how you play, so a game can be judged after it: where the time went, what paid and what was bought, when the kit was complete, what killed you, and how smooth the frames were. Pause → Download play log saves it as world-explorer-log-<date>.json; bin/play-log <file> turns it into a report. The code is src/js/play_log.js.

Privacy

The log is kept in this browser's storage and nowhere else. Nothing is sent; the downloaded file is the only way it leaves the device. The pause panel says so in one line. Clear log empties it (Undo brings it back until you resume). The dev page (build/dev.html) and the agent's page keep logs of their own, as they keep saves of their own.

What it records

• Sessions. A session is one game from its start (new, continue, load) to the main menu or the page's close; past an hour of play it goes on in a new session of the same game, which begins with the world and the kit. It carries the mode (campaign, arcade or race, the main menu's Races), the difficulty, the game's version and build time, and how it began and ended.
• Games (runs). A campaign is one run across all its sessions: its save keeps the id (campaign.log_run), so a continue next week joins the same run. Each arcade run is a run of its own. In the Races mode the races from the menu back to the menu are one run, each race a run event in it.
• Records. One record a minute of play, cut short when you change worlds, load, or die, so each record is in one world. A record holds the salvage on hand, salvage earned by source and spent by kind, XP by source, kills by raider type, damage dealt and taken (by cause), raider shots, dashes, pulses, supplies used, deaths, the lowest hull, and the frame rate.
• Events. A world entered, a purchase, a sale, the kit when it changed, a rank, a contract's steps, a flagship killed, a race, an arcade wave and a world cleared, a death with its cause, the milestones (the top ship, every module at its cap, every gun at tier 5), a load or a tow.

Only play counts toward time: flight, and the station, depot, map and inventory screens. Pause, menus, settings and the results screens do not.

Size

All stored sessions together are kept under 1.5 million characters (about 1.5 MB, some 40 hours of play); past it the oldest sessions go first. Saves come first: when the browser's storage is full, the log's oldest sessions make room for a save (storage_set). The pause panel says how many sessions were dropped. A session longer than the cap would lose its oldest records, and say how many in dropped; the hourly roll keeps sessions far below it.

Cost

In a frame the log only adds to counters it already holds: no objects, no strings. It writes once a minute (the session being played: an hour at most, about 45 KB, under a millisecond), on pause, at a death and when the page is hidden or closed. bin/perf shows no change in frame time or allocation.

The file

One JSON document. Each record and each event sits on a line of its own, so it reads as text and loads as JSON.

{
 "format": "world-explorer-play-log",
 "format_version": 1,
 "about": "…",
 "exported_at": "2026-10-13T20:46:00.000Z",
 "game": {"version": "0.1.0", "built": "2026-10-13T20:42:31.451Z"},
 "summary": {…},
 "sessions": [{…}, …]
}

format_version grows when a field changes meaning or goes away; new fields can come without it. A reader skips fields it does not know.

Units

summary

A session

A record

{"t":60,"s":53,"at":"…","world":"Haven","flight_s":47,"docked_s":6,"salvage":970,
 "earned":{"contract":290,"race":190,"sell ore":80},"spent":{"trade":24},
 "xp_total":262,"xp":{"kill":14,"contract":206},"rank":"Courier",
 "kills":{"chaser":2,"shooter":2,"lancer":1},"elite_kills":0,"dealt":1180,
 "taken":{"shield":0,"hull":53},"taken_by":{"shot":53},"raider_shots":28,"hits_on_you":4,
 "dashes":3,"pulses":1,"supplies":{"emp":1},"deaths":0,"hull_low":0.41,
 "fps":59.8,"frame_ms":{"avg":16.7,"max":34,"over_33":1,"over_50":0,"over_100":0},
 "work_ms":{"avg":3.1,"max":12.4},"paint_ms":{"avg":4.2,"max":15.8}}

unlogged is salvage or XP that moved without passing a hook the log knows (a dev cheat, or a new source in the code): the sums always match the balance, and a non-zero unlogged says a hook is missing.

Events

Every event has t and type.

Reading it

bin/play-log world-explorer-log-2026-10-13-2346.json
bin/play-log log.json --charts=data/play-log    # PNG charts too
bin/play-log log.json --mode=campaign
bin/play-log log.json --mode=race               # the Races mode only

The report has the sessions and games, per world time, income, spending and kills, income by source and spending by kind, salvage on hand over time, the kit as it changed, the priciest purchases, when the game was maxed out and what the salvage did after, combat per world, deaths, contracts, flagships, races (the Races mode's each with its place, time, par, gap to the best rival, crashes and hull left, a summary per difficulty, and your place at each ring), the arcade's worlds, the frame rate, and notes on what stands out.

In Python:

import json, pandas as pd
log = json.load(open('world-explorer-log.json'))
records = pd.json_normalize([dict(r, session=s['id'], mode=s['mode']) for s in log['sessions'] for r in s['records']])
events = pd.json_normalize([dict(e, session=s['id']) for s in log['sessions'] for e in s['events']])

With jq, every purchase over 1000:

jq -c '.sessions[].events[] | select(.type == "buy" and .price > 1000)' log.json