Everything on this page is optional and can be switched off: the faithful 1988 game is the base mode.

The references to source files and binary offsets you'll see here are the provenance of each claim: they say where it comes from. The engine is published under GPL-3.0-or-later at github.com/kokoima/openu5, so you can go and look them up one by one.

What the port does differently

Three documents with before / after comparisons of what this port does differently from the Ultima V of 1988 and — the part that matters a year from now — why each thing is the way it is, and what was given up to get it.

The distinction that makes the rest useful

This section lists what the port offers: things the original did not do, each one optional and with its own switch. The defects of ours that we have been fixing — the ones that only put the game back the way 1988 had it — are no longer listed here as improvements: fixing what we broke does not improve the game, and mixing it in with the offer is what makes documents like this age badly. Every entry carries a tag:

The ✨ entries are the ones that literally answer "improvements made by the port" — and today that is every entry in the table.

The rule that decides what belongs here

An improvement may change how you reach the game. It may never change what the game does.

Nothing in these four documents touches a rule: not a roll, not a price, not a schedule, not an outcome. That is the line, and when something crosses it, it stops being an improvement and becomes a declared divergence, with its ⚖️ tag and its reason written down.

The check is concrete, not a statement of intent: the engine is deterministic, so a session recorded with touch controls replays identically on a keyboard. If an improvement changed what the engine computes, that replay would stop matching.

What we will not improve

These are the things we have been asked for and will not do. They are written here so the boundary is visible rather than a matter of taste, and so nobody has to ask twice.

And one that needs more care than the others, because the answer is not "no": upscaled art. The tiles come out of your files and are never redrawn — but the port does offer xBR smoothing, and today that is the default skin on startup. That is not new art: it is a filter over the same pixels, reversible with a switch, and the faithful skin leaves the image byte-for-byte as the original. It is documented in 1 · Image improvements with what it gains and what it costs. What we will not do is upscale with a generative model: that would be another game's art.

Rules these documents follow

• Every claim comes from one of two sources: code read in this tree (with path and line), or an internal engineering record cited by name. Where one of those sources has turned out to be stale, that is said.
• Trade-offs get written down. If something was gained at the cost of something else, it is in the text. A comparison without the cost is advertising.
• Figures carry a date. A number without its moment is a snapshot someone will read as the present.
• Every ## N · entry declares its tag and its summary, in that order and before the first ###: first a line that STARTS with 🎯/✨/⚖️/🗑️, then a whole line in italics saying in one sentence what it is. That is where the table above comes from, and it builds itself: an entry with no tag or no summary turns the build red instead of quietly dropping out of the table. (If the tag line already carries that sentence right after the emoji — with no TAG — the sentence serves as the summary.)

A note on the images

The screenshots on these pages contain graphics from the original game. They are shown here, on this site, because seeing the difference is the entire point of a before/after.

They do not travel to the source repository. The two destinations diverge on purpose, and the reason is worth stating plainly: a deployed site can show screenshots of the work it describes; a repository published under a free software licence cannot carry third-party artwork. Same project, two rules, each declared where it applies.